// // In Javascript, there are 7 data types that we can use. // 1. Numbers // 2. String // 3. Boolean // 4. Undefined // 5. Null // 6. Array // 7. Object // // All numbers in JavaScript are 64-bit floating point numbers, i.e. double. var num_1 = 55; var num_2 = 0.55; var num_3 = 22/7; var num_4 = num_1 + num_2 + num_3; document.write(typeof num_1 + "
"); document.write(typeof num_2 + "
"); document.write(typeof num_3 + "
"); document.write(num_4 + "
"); // String in Javascript var str_1 = "I learn " var str_2 = 'Javascript' var str_3 = str_1 + str_2; document.write(typeof str_1 + "
"); document.write(typeof str_2 + "
"); document.write(str_3 + "
"); // Problem when adding two float variables var float_1 = 0.1 + 0.2; var float_2 = 0.3 + 0.6; document.write(float_1 + "
"); document.write(float_2 + "
"); // How to solve it by doing multiplication and division first var float_3 = (0.1 * 10 + 0.2 * 10) / 10; var float_4 = (0.3 * 10 + 0.6 * 10) / 10; document.write(float_3 + "
"); document.write(float_4 + "
"); // Boolean in Javascript var bool_1 = 5 == 5 && 7 > 8 ; var bool_2 = bool_1 || 8 >= 5 ; document.write(typeof bool_1 + "
"); document.write(typeof bool_2 + "
"); document.write(bool_1 + "
"); document.write(bool_2 + "
"); // Undefined and Null // Null is a special object in javascript that indicates "no value" var miss_1; var miss_2 = null; document.write(typeof miss_1 + "
"); document.write(miss_2 + "
") document.write(typeof miss_2 + "
"); // Array in Javascript // Array is a variable that contains many value (element) such as string, // numbers, boolean, etc var array_1 = [1.5, "This is Code", true]; // Index on array start from 0, so 1st element on index 0, 2nd element on // index 1, and so on. document.write(array_1[1] + "
"); document.write(array_1[3] + "
"); // Output will be undefined // Adding new element on array array_1[3] = array_1[0] + 0.5; document.write(array_1[3] + "
"); // Output will be 2 document.write(array_1.toString() + "
"); // Display array as a string document.write(array_1.length + "
"); // Display how much element on array // Delete element on array delete array_1[0]; document.write(array_1[0] + "
"); // Output will be undefined // Function in Javascript // Function Expression (Anonymous Function) var num_5 = parseInt(prompt("Input 1st number : ")); var num_6 = parseInt(prompt("Input 2nd number : ")); var add = function(num_5,num_6){ var result = num_5 + num_6; return result; }; // Assign a result to the variable var other_add = add(num_5,num_6); document.write(typeof add + "
"); document.write(other_add + "
"); // Function Declaration (Named Function) function who_am_i(){ document.write("I am " + name + "
"); } var name = "Chuck Norris"; who_am_i(name); // Declaring Object in Javascript var vehicle = {car:"Bentley",motorcycle:"Ducati",airplane:"Boeing-737"}; // Calling a Property from Object document.write(vehicle.airplane + "
"); document.write(vehicle.jet + "
"); // Output will be undefined because property ship does not exist // Adding new properties to an existing object vehicle.jet = "F-22 Raptor"; document.write(vehicle.jet);

Data Types on JS