better (usable) ajax worker

script.js

//your main script
function ParalellAjax(){
    var ajaxWorker = new Worker('worker.js');
    var i = 0;
    var cbs = [];
    this.close = function(){
        ajaxWorker.close();
    };
    ajaxWorker.onmessage = function(e){
        var cb = cbs[e.data[0]];
        cb(null,e.data[1]);
    };
    this.data = function(url,callback){
        var j = i++;
        cbs[j] = callback;
        ajaxWorker.postMessage([j,url]);
    }
}

worker.js

//your worker
var quickAjax = function(url,callback){
    var ajax = new XMLHttpRequest();
	ajax.onreadystatechange = function(resp){
    	if(ajax.readyState === 4 && ajax.status === 200) {
			calback(JSON.stringify(ajax.response));
		}
	}
	ajax.open('GET',url,true);
	ajax.send();
}
self.onmessage = function(e){
    quickAjax(e.data[1],function(resp){
        self.postMessage([e.data[0],resp]);
    });
}