I have the following ajax fucntion:

function ajax(value, url, urlVarname, displayContainers_id){    
    if(value == ''){
        document.getElementById(displayContainers_id).innerHTML='';
    }
    /* THIS IS LINE 12*/ xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange=function()
    {
        if(xmlhttp.readyState == 4 && xmlhttp.status == 200){
            document.getElementById(displayContainers_id).innerHTML=xmlhttp.responseText;
        }

    }
    xmlhttp.open('GET',url + '?varName=' + urlVarname + '&value=' + value, true);
    /* THIS IS LINE 25 */ xmlhttp.send();
}

 onmousedown="ajax(document.getElementById('searchParamater').value, 'http://192.168.0.7/controllers/search_controller.php', document.getElementById('searchBy').value, 'ajaxBucket')">

This whole thing works fine in firefox but when i use prism 0.9, it malfunctions and i get the following error in the errors console:

Warning: assignment to undeclared variable xmlhttp Source File: http://192.168.0.7/javascript/main.js Line: 12

Error: uncaught exception: [Exception... "Not enough arguments [nsIXMLHttpRequest.send]" nsresult: "0x80570001 (NS_ERROR_XPC_NOT_ENOUGH_ARGS)" location: "JS frame :: http://192.168.0.7/javascript/main.js :: ajax :: line 25" data: no]