function createRequestObject() {
    var ro;
    if(isIE()){
        ro = new ActiveXObject("Msxml2.XMLHTTP");

         if (ro.overrideMimeType) {
            ro.overrideMimeType('text/xml');
         }
    }else{
        ro = new XMLHttpRequest();
    }
    return ro;
}

function doAjaxCall(http, method, url, returnfunction, params){
    http.open(method, url);

    if(method == 'POST' || method == 'post'){
        try{
            http.setRequestHeader("Content-type","application/x-www-form-urlencoded");
            http.setRequestHeader("Content-length", params.length);
        }catch( e ){}
    }

    if(returnfunction){
        http.onreadystatechange = returnfunction;
    }

    try{
        http.send(params);
    }catch(e){}
}