'use strict'; // uncomment this and set the protocol to match the url (http/https) if necessary. var corstest = '';//'https://cors-anywhere.herokuapp.com/'; var selectedMethod = 1; var selectedURL = 0; var methods = ['GET','HEAD','POST','PUT','DELETE','CONNECT','OPTIONS','TRACE','PATCH']; var urls = ['https://entrusters.com/templates/yoo_moustache/favicon.ico', 'http://baseshare.com/ArtistUpload.mp3', 'https://hinthint.com/', 'https://www.msn.com/', ]; function doRequest(uri, callback){ var xhr = new XMLHttpRequest(); xhr.open(methods[selectedMethod], uri); xhr.onreadystatechange = function() { if(this.readyState == this.HEADERS_RECEIVED) callback(this.getAllResponseHeaders()); if (this.readyState == this.DONE) callback(this); }; xhr.send(); } var hilite = {'responseURL':1, 'status':1, 'statusText':1}; function cb(res){ if(typeof(res)==='object') { // separate the interesting fields for(var i in hilite) { var style = ' style="color:crimson"'; document.write("" + i + ": " + res[i] + "
"); } // print the rest document.write("

"); for(var i in res) { var style = ' style="color:#777"'; if(hilite[i]===1) continue;//style = ' style="color:crimson"'; document.write("" + i + ":

" + (res[i]+"").replace(//g,'>') + "

"); } } else document.write('Response Headers:

' + res + '

'); document.write("

"); } window.onload=function(){ document.write("Demonstrates how to do a low-impact HEAD (does resource exist?) request to a webserver
Python version ... status below in red.

"); doRequest(corstest + urls[selectedURL], cb); }

File exists (HEAD) request with JS