Problem in getting Http Response in chrome

Am trying to get http response from php web service in javascript, but getting null in firefox and chrome. plz tell me where am doing mistake here is my code,

function fetch_details()
{
 if (window.XMLHttpRequest)
 {
  xhttp=new XMLHttpRequest()
  alert("first");
 }
else
 {
  xhttp=new ActiveXObject("Microsoft.XMLHTTP")
  alert("sec");
 }
 xhttp.open("GET","url.com",false);
 xhttp.send("");
 xmlDoc=xhttp.responseXML;
 alert(xmlDoc.getElementsByTagName("Inbox")[0].childNodes[0].nodeValue);
}

I have tried with ajax also but am not getting http response here is my code, please guide me

var xmlhttp = null;
var url = "url.com"; 
if (window.XMLHttpRequest) 
{ 
   xmlhttp = new XMLHttpRequest(); 
   alert(xmlhttp); //make sure that Browser supports overrideMimeType 
   if ( typeof xmlhttp.overrideMimeType != 'undefined') 
   {                     
      xmlhttp.overrideMimeType('text/xml'); 
   } 
} 
else if (window.ActiveXObject) 
{ 
   xmlhttp = new开发者_高级运维 ActiveXObject("Microsoft.XMLHTTP");
}
else
{ 
   alert('Perhaps your browser does not support xmlhttprequests?'); 
} 

xmlhttp.open('GET', url, true);
xmlhttp.onreadystatechange = function() {

if (xmlhttp.readyState == 4)
{
   alert(xmlhttp.responseXML);
} 
};

}

// Make the actual request xmlhttp.send(null);

I am getting xmlhttp.readyState = 4 xmlhttp.status = 0 xmlhttp.responseText = ""

plz tell me where am doing mistake

Your doing a cross domain request.

You are only allowed to do xmlhttp requests to the same host.

I can't read any of that but Chrome has a JavaScript console that will probably tell you what you're doing wrong.

It's a cross-domain issue, to resolve it the server response header should contain "access-control-allow-origin"

If your server is coded in PHP, the header should be like the following example:

<?php
    header('Content-type: text/html');
    header('Access-Control-Allow-Origin: *');
    $uri = 'http'. ($_SERVER['HTTPS'] ? 's' : null) .'://'. $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    echo('<p>This information has come from <a href="' . $uri . '">' . $uri . '</a></p>');
?>