Simple Javascript function to place a xmlhttp request (supporting a range of browsers) and trigger a callback function once the request has been satisfied
This is one of the functions I often find myself looking at older projects to find rather than re-writing it. Yes you can do the same with jQuery, but that's only really a valid route if you're already loading jQuery. Otherwise you're loading an entire framework for no real benefit
function fetchPage(url,callback,errcallback){
var xmlhttp;
if (window.XMLHttpRequest){
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}else{
// code for IE6, IE5 (why am I still supporting these? Die... Die.... Die....
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function(){
if (xmlhttp.readyState==4){
if (xmlhttp.status==200){
callback(xmlhttp.responseText)
}else{
errcallback(xmlhttp.responseText)
}
}
}
xmlhttp.open("GET",url,true);
xmlhttp.send();
}
var success = alert;
var error = console.log;
fetchJSON('sitemap.json',success,error);