Q:

Is there any data limit size for ajax xmlhttprequest post method my xhr get cut off?

I am trying to send some html data to php script using ajax xmlhttprequest post method. But for some reason My XHR POST REQUEST is cut off and not all data get transferred to my doit.php script. However the same html data from textarea form get passed to doit.php script correctly via normal form post method! could you guys help me overcome this problem and be able to pass this html data via xhr request ?
    var xmlhttp;
    if (window.XMLHttpRequest)
      {// code for IE7+, Firefox, Chrome, Opera, Safari
      xmlhttp=new XMLHttpRequest();
      }
    else
      {// code for IE6, IE5
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    xmlhttp.onreadystatechange=function()
      {
      if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
        document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
        }
      }
    xmlhttp.open("POST","http://www.mysite.com/doit.php?Name=test&Id=12345",true);
    xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
    xmlhttp.send("outputtext="+siteContents);

A:

I think you should also encodeURIComponent() your siteContents string:
xmlhttp.send("outputtext=" + encodeURIComponent(siteContents));

That's because POST variables are delimited by an ampersand (&). The problem probably is  that your string is also containing an ampersand which will be interpret as the beginning of a new POST variable.

You could easily check this if you output all received POST variables in your PHP script:
var_dump($_POST);

