Dear All, Please help to advise how to solve my simple problem which made me in trouble i am an new learner of ajax and to try simple application as below: <!DOCTYPE html> <html> <body> <h1>The XMLHttpRequest Object</h1> <button type="button" onclick="loadDoc()">Request data</button> <p id="demo"></p> <script> function loadDoc() { var xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function() { if (this.readyState == 4 && this.status == 200) { document.getElementById("demo").innerHTML = this.responseText; } }; xhttp.open("GET", "test.txt"); xhttp.send(); } </script> </body> </html> But there was error message of "Failed to load resource: the server responded with a status of 404 (Not Found)" which was shown by development tool of browser and pointed at "xhttp.send()" After checking, the server should be working in normal condition Attached please find the screenshot of messages which were generated by both of server and browser Thank you for your kind attention andrewmung may I get your help.pdf