Alfresco规则和Ajax

Question

I'm quite new to Alfresco and have been tasked with creating a rule that calls an external php script whenever a folder is created. There doesn't seem to be a lot of information out there that indicates that this is possible. I tried to create a script like the following, but I receive an "XMLHttpRequest not defined error":

function submitDoc(url, params){
    var http = new XMLHttpRequest();
    http.open("POST", url, true);

    //Send the proper header information along with the request
    http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    http.setRequestHeader("Content-length", params.length);
    http.setRequestHeader("Connection", "close");

    http.onreadystatechange = function() {
        if(http.readyState == 4 && http.status == 200) {
            logger.system.out("SUCCESS!");
        }
        else{
            logger.system.out("Failure: "+http.status);
        }
    }
    http.send(params);
}
submitDoc("/addPage.php", "var1=somevar");