//https://www.youtube.com/watch?v=vEROU2XtPR8&feature=youtu.be&t=1947%22 //THIS SECTION RELATES TO THIS VIDEO //--------------------------------------------------------------------- //The Alert function. Use to test if .js and HTML are linked. console.log('Start video at 41:55'); //Alert() with a capital "A" does not work. //--------------------------------------------------------------------- //VARIABLES /*Variables can contain letters, numbers, underscores, and dollar signs*/ //Variables should begin with a letter //Can be started with an underscore/dollar sign for diff reasons //--------------------------------------------------------------------- //Establish 2 variables as numbers and add them within an alert. var number1 = 35; var number2 = 40; console.log(number1 + number2); //If we put quoets around the numbers they becomes strings. var number1 = '35'; var number2 = '40'; console.log(number1 + number2); //You can also add strings and variables. var number1 = '35'; var number2 = '40'; console.log('my favorite number is ' + number2); //Javascript is case sensitive as seen below var test = 'This is a test'; var Test = 'This is another test'; console.log(test); console.log(Test); //--------------------------------------------------------------------- //Below I declare these variables without a value. //This is okay, I can define the value later. //Until I declare the value, the variables value is undefined //Camel Case var myFavoriteNumber; //Partial Case var MyFavoriteNumber; //Underscore Style var my_favorite_number; //Here I am adding value to the above variables myFavoriteNumber = 5; MyFavoriteNumber = 5; my_favorite_number = 5; console.log(myFavoriteNumber + MyFavoriteNumber + my_favorite_number); //--------------------------------------------------------------------- //ARRAYS //Arrays are used to store multiple values in a single variable. //This is an initialized array. var colors = [] //This is an array with 3 different values or colors. var colors = ['red', 'blue', 'orange'] //This alert will add all the colors as a string. console.log(colors); //Access the first value of an array console.log(colors[0]); //Access the second value of an array console.log(colors[1]); //Access the third value of an array console.log(colors[2]); //--------------------------------------------------------------------- //Arrays are zero based with zero being the first value. //--------------------------------------------------------------------- //This is how we add values to an existing array. colors[3] = 'green'; console.log(colors); console.log(colors[3]); //Here is a more effective way to add values to an array. colors.push('purple') console.log(colors); console.log(colors[4]); //--------------------------------------------------------------------- //Here is an array with numbers. //Notice how you can put a string in an array of numbers. var numbers = [5,77,6,'Seven', 1, 55]; //We can add different values from the array. console.log(numbers[0] + numbers[2]); //Accessing the string. console.log(numbers[3]); //--------------------------------------------------------------------- //How to tell how many values your array has. console.log(numbers.length); //How to see your values in numbered/alphabetical order. console.log(numbers.sort()); //How to display your values in a reversed order. console.log(numbers.reverse()); //--------------------------------------------------------------------- //Console log, press f12 in chrome to access console.log('HELLO'); //--------------------------------------------------------------------- //for Loops //Below this loop sets variable i = 0 //Then it tells the loop to run until as long as i < 10 //Then it says add 1 to i as far as it can until i < 10 or = to 9 //See the console log for display for(var i = 0; i < 10; i++){ console.log(i); } //This log is to break up the data. console.log('Breakpoint'); //This next log will include the number 10 in the loop for(var i = 0; i <= 10; i++){ console.log(i); }; //Here we include a string in the loop. for(var i = 0; i <= 10; i++){ console.log("I love the number " + i); }; //--------------------------------------------------------------------- //While loop //Establish the variable. var i = 0; //The while loop while(i < 10){ console.log(i); i++ }; //--------------------------------------------------------------------- //For each loops are used for arrays var numbers =[33,54,76,34,2,6]; //For each loop //This loop will cycle through all of the values in the array numbers.forEach(function(number){ console.log(number); }); //--------------------------------------------------------------------- //You still can use for loops for arrays as well. for(var i = 0; i < numbers.length; i++){ console.log(numbers[i]); }; //--------------------------------------------------------------------- //I can tell the numbers to be output in reverse too. numbers.reverse(); //Then run the for each loop again. numbers.forEach(function(number){ console.log(number); }); //--------------------------------------------------------------------- //CONDTIONALS //--------------------------------------------------------------------- //if statments if(1 == 1){ console.log('This is true') }; //--------------------------------------------------------------------- // "=" is an assisgnment operator // "==" means equal to // "===" means equal to in value and data type // "!=" means not equal to // "&&" means and // "||" means or //--------------------------------------------------------------------- //The condition below is not true so it will not be logged. if(1 == 2){ console.log('This is true') }; //--------------------------------------------------------------------- //Here is an example with variables where they are not equal var var1 = 3; var var2 = 4; if(var1 != var2){ console.log('Var1 is not equal to Var2') }; //--------------------------------------------------------------------- //Here is an example declaring what to do if the variables are not true if(var1 == var2){ console.log('These variables are equal') } else { console.log('These variables are not equal') }; //--------------------------------------------------------------------- //Here you can see we use more than 1 condition using && or 'and' var var1 = 3; var var2 = 3; if(var1 == var2 && var1 == 3){ console.log('This is true var1 is equal to var2 and 3') } else { console.log('This is flase') }; //--------------------------------------------------------------------- //Here you can see we use more than 1 condition using || or 'or' var var1 = 3; var var2 = 7; if(var1 == var2 || var1 == 3){ console.log('This is true var1 is equal to var2 or equal to 3') } else { console.log('This is flase') }; //--------------------------------------------------------------------- //Switch Statements //Switching the var will change the output as seen below //Change apples to bananas and you will get a different display //If the var is undefined or not listed below default will run //--------------------------------------------------------------------- //because fruit is not define, the code will display the default log var fruit; switch(fruit){ case 'banana': console.log('I love bananas'); break; case 'apple': console.log('I love apples'); break; case 'orange': console.log('I love oranges'); break; default: console.log('Please pick a fruit'); }; //--------------------------------------------------------------------- //OBJECTS //--------------------------------------------------------------------- //Object Literal //Here we create an object called person var person = { firstName: 'Brad', lastName: 'Traversy', age: 34, children: ['Brianna', "Nicholas"], //We can also add another object to the object address: { street: '555 something street', city: 'Boston', state: 'MA' } }; //Here we console.log the persons age using a '.' console.log(person.age); //Here we access one of Brad's children console.log(person.children[0]); //Here we access the entire obeject embedded within our object console.log(person.address); //Here we access a specific part of the object console.log(person.address.state); //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //THIS SECTION RELATES TO SOLO LEARN //math operations var x = 10 + 5; console.log(x); //this will output 15 //you can add many numbers together var x = 10; var y = x+22+33+66+88+99; console.log(y); //this will output 318 //you can also multiply, divide, and subtract //--------------------------------------------------------------------- // multiply * // divide / //subtract - // addition + // modulus (%) this operation return the remainder after dividing //--------------------------------------------------------------------- var x = 26%6; var y = ' because 26/6=4 with 2 left over'; console.log(x + y); //--------------------------------------------------------------------- //Increment & Decrement var a = 0; var b = 10; var a = ++b; console.log(a); console.log(b); //--------------------------------------------------------------------- //so this is a hard concept for me to understand but here we go //maybe i should look up an article //watching this video https://www.youtube.com/watch?v=d4W6-mphL7c //so its all about putting the ++ before or after your value //and how that changes the result //the increments operator adds one to its operand //and returns a value //x++ or ++x //the operator is the (++) //the operand is the variable //--------------------------------------------------------------------- //okay so here is something i learned var x = 5; console.log(x++ + ' | the (++) operator after the var doesnt affect the value until checked later'); console.log(x + ' | this equals 6 becuase the (++) value was applied in the earlier operation, incrementing this result by 1') //so we declare a variable, and if we us the ++ operator after the value //it affects the var in every operation moving forward //here is an example where we put the operator before the variable var y = 5; console.log(++y + ' | putting the ++ operator before the var immediatly affects its value') console.log(y + ' | even if we log the var again, the value still remains 6') console.log(++y + ' | here we do the same operation again, making the result 7') //--------------------------------------------------------------------- //Decrements work the exact same way, except they are used to subtract 1 //--y will affect the value immediatly //y-- will affect the value moving forward var y = 5; console.log(y--) console.log(y) //Here the value of y decreases upon the 2ns console.log var y = 5; console.log(--y); //Here we see that y is changed to 4 immediatly //--------------------------------------------------------------------- //asignment operators //here i will list examples of all types of assisngment operators //--------------------------------------------------------------------- //x=y //this example we assign x the value of y var x = 10; var y = 20; console.log(x=y +' | here x is asisgned the value of y making the result 20 even though x was originally 10'); //--------------------------------------------------------------------- //x+=y //so in this result doing x+=y added both the value of x and y var x = 10; var y = 20; console.log((x+=y)+' | x+=y just added the value of x and y resulting in 30' ); //--------------------------------------------------------------------- //x-=y //in thie result x-=y subtracts y from x var x = 100 var y = 50 console.log((x-=y)+' | this results in 50 because x-=y is the same as x-y'); //--------------------------------------------------------------------- //x*=y //in this result x*=y is the same as x*y var x = 10; var y = 10; console.log((x*=y) + ' | this results in 100 because x*=y is the same as x*y'); //--------------------------------------------------------------------- //x/=y //in this results x/=y is the same as x/y var x = 100 var y = 10 console.log((x/=y) + ' | this results in 10 because x/=y is the same as x/y') //--------------------------------------------------------------------- //x&=y //in this result x%=y is the same as x % y var x = 32 var y = 3 console.log((x%=y) + ' | this results in 2 because x%=y is the same as x%y') //--------------------------------------------------------------------- //comparison operators //these type of operators return true or false //the equal to (==) operator checks whether or not the values are equal var x = 10; var y = 12; //this log will return false because x is not equal to y console.log(x==y) //--------------------------------------------------------------------- //here i will list all types of comparison operators //--------------------------------------------------------------------- // === identical operator //checks to see if variables are identical and of the same data type var x = 1; var y = '1'; //this will return false because they are not the same data type console.log(x===y); var x = 1; var y = 1; //this will return true because they are the same value and data type console.log(x===y); //--------------------------------------------------------------------- // != not equal to var x = 1; var y = 1; //will result in false because the values are equal console.log(x != y); //--------------------------------------------------------------------- // !== not identical var x = 1; var y = '1'; //will result in true because they are equal but not identical console.log(x!==y); //--------------------------------------------------------------------- // > greater than var x = 100; var y = 120; //will result in false because x is not greater than y console.log(x>y); //--------------------------------------------------------------------- // >= greater than or equal to var x = 1; var y = 1; //will be true because x is greater than or equal to y console.log(x>=y); //--------------------------------------------------------------------- // < less than var x = 1; var y = 0; //will be true because y is less than x console.log(y2) && (10<15)); //--------------------------------------------------------------------- //conditional operator //here we change the value of a variable based on a conditon var age=18; var bob = (age >= 21)?'can drink': 'cant drink'; //here we will get the result cant drink because bob is 18 console.log(bob); //lets make him 21 var age =21; var bob = (age >= 21)?'can drink': 'cant drink'; //now he can drink console.log(bob); //--------------------------------------------------------------------- //if statements var x=100; var y=200; if(xy){ console.log('100 is greater than 200 huh') } else{ console.log('100 is not greater than 200 so ill do this instead'); } //the else operation will be performed if the statement is not true //allows us to determin what happens if our operation is not true //--------------------------------------------------------------------- //the else if statement //this allows us to add multiple conditions to an operation //you can write more than 1 else if statement //you are not limited to just one var x = 1000; var y = 2000; var z = 1500; if(x>y){console.log('BOOOOOM')} else if (x == 1000){console.log('you got it phillip')} else{console.log('you didnt get it phillip');} //--------------------------------------------------------------------- //the switch statement is used to replace multiple if statements //can have has many cases as you need //the below statement will output tuesday var day=2; switch (day){ case 1: console.log('monday') break; case 2: console.log('tuesday') break; case 3: console.log('wednesday') break case 4: console.log('thursday') break; default: console.log('anotherDay'); } //switch statements ususally include a case for each possible outcome //default will run if there is no case that matches //the default section and be omitted if there is not need to handle //a case when no match can be found //--------------------------------------------------------------------- //Loops //loops execute a block of code a number of times //3 types of loops //for loops //while loops //do while loops //for loop //this loop contains 3 statements //the first statement can be omitted if your variable has already //been defined //the second statement can be omitted as well, but if you do //you have to provide a break; otherwise the loop will run forever for(i=1; i<=5; i++){ console.log(i + ' the for loop'); } //so this loop is saying that i = 1 //if i is less than 5, then the loop will increment by 1 until //the condition is no longer met //in this case until i is <=5 //the last number in the loop will be 5 //here is another exmaple of how you could do a for loop differently //IF YOU DO OMIT A STATEMENT, YOU MUST STILL PROVIDE A SEMICOLON var i = 0; for(;i<10;){ console.log(i + ' different way to write for loop'); i++; } //--------------------------------------------------------------------- //the while loop //this type of loop will repeat through a block of code //so long as the condition remains true //the syntax /* while (condition) { code block } */ //here is an exmaple of the while loop var i = 0; while(i<10){ console.log(i + ' the while loop'); i++; } //--------------------------------------------------------------------- //the do while loop //this loop is like the while loop, expect it will run the targeted block //of code once, and then check the condition, and then run the loop /* Syntax for the do while loop do { code block } while (condition); */ //the do while loop var i = 20; do{ console.log(i + ' the do while loop'); i++; } while (i<=25); //the do while loop will run atleast one cycle, even if the condition is false //--------------------------------------------------------------------- //using the break statement //the break statement jumps out of a loop and will continue to run code //after the loop //example for (i=0; i<10; i++){ if(i===5){ break; } console.log(i + ' this is an example of using the break statement'); } //--------------------------------------------------------------------- //the continue statement //this statmenet breaks only one iteration of a loop and continues //the loop after that iteration //example of using the continue statement //in this loop, value 5 will be skipped for(i=0; i<=10; i++){ if(i==5){ continue; } console.log(i + ' this is an exmaple of the continue statement'); } //be careful writing condition, they can cause the loop to run forever //same thing if you forget to increase the variable //--------------------------------------------------------------------- //javascript functions //--------------------------------------------------------------------- //user defined functions //a function is a block of code designed to perform a particular task. //code reuse: is where you can define the code once and use it many times //--------------------------------------------------------------------- /* the syntax */ /* function name(){ code to be executed } */ //--------------------------------------------------------------------- /* Function names can contain letters, digites, underscores, and dollar signs (same rules as variables) */ /* to execute a function you need to call it. we call functions by name. */ //once a function is defined, javascript allows you to call it //as many times as you want. //example of a function function myfunction(){ console.log('you wrote a function'); } //here we call on the function 3 different times myfunction(); myfunction(); myfunction(); //--------------------------------------------------------------------- //functions can take parameters //parameters are names //parameters are the names listed in the functions definition //be sure to seperate names by commas //syntax /* functionName(param1, param2, param3) { // some code } */ //--------------------------------------------------------------------- //after defining parameters, you can use them in your functions function sayHello(name){ console.log('Hi,' + name); } sayHello('David'); //function arguments are the real values passed to (and recieved by) //the function //here is an example with many parameters function fruitLove(type){ console.log(type); } fruitLove('Bananas'); fruitLove('Apples') fruitLove('Limes') //if the code fails, make sure your name is long enough //you can also use multiple parameters within a function by //seperating them with a comma function sayHello(name, age){ console.log(name + ' is ' + age + ' years old.'); } sayHello('phil', 25); sayHello('katie', 25); sayHello('melody', 3); //function parameters are listed in the function definition //if you pass more arguments than are defines, they will be assigned //to an array called arguments //if a function is called with missing arguments (fewer than declared) //then the missing values are set as undefined, which indicates //a variable has not been assigned a value //--------------------------------------------------------------------- //function return statement //a function can have a return statement //it is used to return the value of a function //useful for calculations //when javascript reaches a return statement, the function stops executing //exmaple //here is the function function myFunction(a,b){ return a * b; } //we assign a var the function name //we replace a and b with real values //we console log to see the calculation var x = myFunction(5,6); console.log(x); //this displays 30 var x = myFunction(100,10); console.log(x); //this displays 1000 //so we can run multiple calculations with functions we set up //here is another example function addNumbers(a, b){ var c=a+b; return c; } console.log(addNumbers(40,2)) //--------------------------------------------------------------------- //alert box trick //write '/n' to line break in an alert box //--------------------------------------------------------------------- //the prompt box //has the user input a value upon entering a webpage //example /* var user=prompt('please enter your name'); alert(user); */ //--------------------------------------------------------------------- //confirm box //used when we need the user to verify or accept something //exmaple /* var result = confirm('Do you really want to leave this pagE?'); if(result == true){ alert('Thanks for visiting'); } else{ alert('Thanks for staying with us'); } */ //--------------------------------------------------------------------- //javascript objects //objects are variables //objects contain many values //think of objects as a list of values //name:value pairs //names and values are seperated by a colon //exmaple /* var person = { name:'John', age:31, favColor:'green', height:188 } */ //--------------------------------------------------------------------- //javescript objects are containers for named values console.log(person) //accessing values //first we need an object var Melody = { name:'Melody', age:3, favoriteMovie:'Frozen', height:'2foot', favColor:'blue', bday:'October 20th, 2015', timeOfBirth:'9:30PM' } console.log(Melody) //accessing values of an object var x = Melody.age; var y = Melody.height; console.log(x); console.log(y); console.log(Melody.bday); //objects are a core concept in Javascript //you can check the length of a string using the code below //this outputs 6 because the name Melody has 6 characters console.log(Melody.name.length + ' | Melody has 6 characters'); //--------------------------------------------------------------------- //obejct methods //an object method is a property that contains a function definition //here is the syntax //objectNmae.methodName() //methods are functions that are stored as object properties // (OBJECT) . (PROPERTY) // HAIR.COLOR // FACE.STRUCTURE // HEAD.SHAPE //--------------------------------------------------------------------- //object constructor function function Person(name, age, color){ this.name = name; this.age = age; this.color = color; } //here we create new objects based above the function above var p1 = new Person('John', 42, 'green'); var p2 = new Person ('Katie', 25, 'pink'); //this out puts katie becuase that is the name listed under var p2 console.log(p2.name); //--------------------------------------------------------------------- //here is an example of a method //basically a methods are inserted into the constuctor function //here is an exmaple where we us a method to change the name of an object function Person(name, age){ this.name=name; this.age=age; this.changeName = function (name){ this.name=name; } } var name1 = new Person('David', 21); console.log(name1.name + ' | this is name 1, prior to changeName'); name1.changeName('John'); console.log(name1.name + ' | this is name 1 again, but displaying a different name'); //--------------------------------------------------------------------- //here we place a method outside of the object constructor function //THIS SECTION WAS REALLY CONFUSING //I DO NOT UNDERSTAND THE CODE BELOW function Parson(name, age){ this.name=name; this.age=age; this.yearOfBirth=bornYear; } function bornYear(){ return 2016 - this.age; } var pear = new Parson('Phillip', 25); console.log(pear.yearOfBirth); //need help to understand //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //--------------------------------------------------------------------- //had to watch a video to understand //--------------------------------------------------------------------- //inserting a method into an object //ok here is the idea //first create an object var Person = { firstName: 'Daniel', lastName: 'Nielsen', age: 25, hairColor: 'Brown', //this is the method being inserted //this function does the same thing as below //its just easier to access fullName: function ( ){ console.log(this.firstName + ' ' + this.lastName); } }; //now we call on the method //the below outputs the function, which output Daniel Nielsen Person.fullName(); //normally if we wanted to access the first and last name we might say //console.log(Person.firstName+ ' ' +Person.lastName); //outputs Daniel Nielsen //the above is a lot of code to write //here is a different way to get the same outcome //we are going to create a method inside the var Person //now we only have to create the method once //check above to see the method //--------------------------------------------------------------------- //okay i watched another video to show me how to insert methods //into object constructors //here is our contructor function peopleMaker(firstName, lastName, age, height){ this.firstName = firstName; this.lastName = lastName; this.age = age; this.height = height; //now we insert the method, which is just a function this.changeName = changeName; function changeName(name){ //when this function is called upon //firstName becomes equal to name within the changeName function this.firstName = name; } } //so now lets create a new person with our constructor var mySelf = new peopleMaker('Phillip', 'England', 25, 180); //now lets test our person to see if its running console.log(mySelf.firstName); console.log(mySelf.lastName); console.log(mySelf.height); console.log(mySelf.age); //now lets call on our method mySelf.changeName('Bart') //now lets check our objects firstName to see if it changed console.log(mySelf.firstName); //the above output Bart so it changed the name of the object mySelf //--------------------------------------------------------------------- //core objects //arrays store multiple values in a single var var course1='HTML'; var course2=' CSS'; var course3=' JS'; console.log(course1+course2+course3); //or we can write the same thing var courses = new Array('HTML', 'CSS', 'JS'); console.log(courses); //or we can access certain parts of the array //this outputs HTML because it is the 1st property in the array console.log(courses[0]) //array indexs are 0 based //the first value is not 1, but 0 instead //if you try to access a value the has not be defined //the system will output 'undefied' //here is another way to write an array //first we esxtablish the array //but we also tell how many values it will contain //this is basically an example of an array constructor //because many different arrays can be derived from this model //and new values can be constructed easily var courses = new Array(3); //then we add the content to the array after establishment courses[0] = 'got '; courses[1] = 'it '; courses[2] = 'right '; console.log(courses[0]+courses[1]+courses[2]); //we can add new courses at anytime courses[3]='C++'; console.log(courses[3]); //an array is a special type of object //objects are accessed by name 'objectName.property' //arrays are accessed by numbers //course[1] vs Courses.class1 //to check the length of an array do the folowwing property //courseName.length //this will output the total number of values within the array //example console.log(courses.length); //this outputs 4 because we have 4 courses in our courses array //if the array were empty the output would be zero //okay so how do we combine existing arrays into a single new array? //first lets create 2 different arrays var people = ['bob','scott','paul','tim']; var places = ['oklahoma','tenessee','flordia','jail']; //ok lets display content console.log(people); console.log(places); console.log('the two arrays above are seperate') //now lets combine them into one array var peoplePlaces = people.concat(places); console.log(peoplePlaces); console.log('now they are one array due to the concat method') //now adding content to the arrays will affect the concated array as well //--------------------------------------------------------------------- //here is an example of an associative array //this is where we give each element in the array a defining name //instead of relying on a index number //this will result in an object and not an authentic array //here is they syntax var person = []; //brackets to establish we are working with an array person['name']='John' person['age']=30; console.log(person['age']) //now we can call the array by name, not by number //outputs 30 //use objects when you want the index to be a string //use arrays when you want the index to be numbers //javascript does not support named array values //--------------------------------------------------------------------- //the math object is an already existing object in javascript //it is really a tool you can use as a shortcut //instead of programming your own math functions //this object has them prestored //the math object /* 1. E = euler's constant 2. LN2 = natural log of the value 2 3. LN10 = natural log of the value 10 4. LOG2E = the base 2 log of eulers constant 5. LOG10E = the bas 10 log of eulers constant 6. PI = returns the constant pi */ //math object methods used for calculations /* 1. abs(x) = returns the absolute value of x 2. acos(x) = returns the arccosine of x, in radians 3. asin(x) = returns the arcsine of x, in radians 4. atan(x) = returns the arctangent of x as a numeric value between -PI/2 and PI/2 radians 5. atan2(y,x) = returns the arctangent of the quotient of its arguments 6. ceil(x) = returns x, rounded up to nearest integer 7. cos(x) = returns the cosine of x (x is in radians) 8. exp(x) = returns the value of E to the power of x 9. floor(x) = returns x, rounded down to the nearest integer 10. log(x) = returns the natural logarithm (base E) of x 11. max(x,y,z) = returns the number with the highest value 12. min(x,y,z) = returns the number with the lowest value 13. pow(x,y) = returns the value of x to the power of y 14. random() = returns a random number between 0 and 1 15. round(x) = rounds x to the nearest integer 16. sin(x) = returns the sine of x (in radians) 17. sqrt(x) = returns the square root of x 18. tan(x) = returns the tangent of an angle */ //you do not need to build the math constructor //there is no need to create a math object first //this idea is built into javascript console.log(Math.PI + ' this is the math object displaying PI'); //--------------------------------------------------------------------- //randomly generated number //here is an example of a randomly generated number between 1 and 10 //everytime this is loaded a random number between 1 and 10 will be logged console.log(Math.ceil(Math.random()*10) + " | a random number"); //--------------------------------------------------------------------- //a program that displays the square root of a given number /* //here we will create a program that will ask the user to input a number //and then it will display the square root of the number var n = prompt('Enter a number', ''); var answer = Math.sqrt(n); alert('The square root of ' + n + ' is ' +answer); */ //math is a handy object and can save you a lot of time //--------------------------------------------------------------------- //the data object //the setIntercal function can be very powerful for animation //setInterval //the setInterval method calls a function of evaluates an expression in intervals //these intervals are defined in milliseconds //here is an exmaple /* function myAlert(){ alert('Fuck You!'); } setInterval(myAlert, 10000); */ //do not include () when passing a function into //the setInterval method //the date obeject //this object allows us to work with the date and time //it looks like this Date() //a date consists of a year, a month, a day, an hour, a minute, a seconds //and a milliscond //example var d = new Date(); console.log(d + ' | todays date'); //we can also access specific dates in different ways //javascript is tracking milliseconds since jan 1st of 1970 //the below will output jan 2nd of 1970 //this is because jan 2nd 1970 is 125000000 milliseconds after jan 1st 1970 var e = new Date(125000000); console.log(e); //we can also display the date as a string //example var e = new Date('July 20, 1993 00:00:00'); console.log(e + ' | my bday'); //then we can also display in the following format //year, month, day, hours, minutes, seconds, milliseconds //exmaple, here is my bday in that format var e = new Date( 93, //year 6,//month (jan = 0, dec = 11) 20,//day 0,//hours 0,//minutes 0,//seconds 0//milliseconds ); console.log(e + ' | still my bday'); //date methods //1.getFullYear() //2.getMonth() //3.getDate() //4.getDay() //5.getHours() //6.getMinutes() //7.getSeconds() //8.getMilliseconds() //example var d = new Date(); //this line pulls the current hour var hours = d.getHours(); //this line dispays the current hour console.log(hours); /* //here we create a program that prints the current time to the browser function printTime(){ var d = new Date(); var hours = d.getHours(); var mins = d.getMinutes(); var secs = d.getSeconds(); document.body.innerHTML = hours+':'+mins+':'+secs; } setInterval(printTime, 1000); */ //above we used the innerHTML property //in the case above we were writing over the content of our body //every seconds //--------------------------------------------------------------------- //JAVASCRIPT NOTES //PROGRAMMING FUNDAMENTALS //Variables //Arrays //Loops //Conditionals //Comparisons and Operators //Objects //Functions //Program Flow //Data Types //Prototypes //Events //DATA TYPES //Numbers //String //Array //Object

Notes 11/12