php - confusion about basic AJAX code -

<script>     try {         function xmldo() {             var xmlhttp;             xmlhttp = new xmlhttprequest();             xmlhttp.onreadystatechange = function () {                 if (xmlhttp.readystate == 4 && xmlhttp.status == 200) {                     document.getelementbyid("para").innerhtml = xmlhttp.responsetext;                 }             }             var url = "http:\\127.0.0.1\ajax.php";             xmlhttp.open("get", url, true);             xmlhttp.send();         }     } catch (err) {         document.write(err.message);     } </script> <p id="para">hey message change</p> <br> <button type="button" onclick="xmldo()">click me</button> 

this code webpage want change content of #para.innerhtml respnse in php file ajax.php

<?php $response="hey text changed"; echo $response; ?> 

i using wamp placed ajax.php in www folder , set location of file on server 127.0.0.1/ajax.php [url] on pressing button text @ para placeholder not getting changed. new ajax must missing on points. plz me them.

change slashes in url.

you have: http:\\127.0.0.1\ajax.php correct way is: http://127.0.0.1/ajax.php

i suggest using jquery perform ajax requests - it's simpler , write less code!

i've added example below written in jquery:

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script> <script type="text/javascript"> $(document).ready(function(){      $("#button_id").click(function(){          $.ajax({             url: 'http://127.0.0.1/ajax.php',             cache: false,             type: 'get',             datatype: 'html',             error: function (e){                 console.log(e);             },             success: function (response){                 $("#para").empty().append(response);             }         });      });  }); </script>  <p id="para">hey message change</p><br> <button type="button" id="button_id">click me</button>