I need to rework a website. I currently have following code:
function combinedServerRequestSync(requestParams) {
    var xmlHttp = new XMLHttpRequest();
    xmlHttp.open('POST', 'utility/php/RequestFile.php', false);
    xmlHttp.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
    xmlHttp.send(requestParams);
    if(xmlHttp.status === 200){
        return xmlHttp.responseText;
    } else{
        return xmlHttp.statusText;
   }
}
the problem with this is, that it freezes the webpage everytime it runs. Is there a solution for this that doesn't evolve rewriting all method calls.
