function beginUpload() {
	showUpload();
}
 
function showUpload() {
	$.getJSON("uploadprogress.php?id=" + progress_key, function(data) {
		if(data == null) {
			return;
		}
		var percentage 	= Math.floor(100 * parseInt(data.bytes_uploaded) / parseInt(data.bytes_total));
        var elem 		= document.getElementById("progressbar");
		var width 		= (550 * percentage) / 100;
		elem.className 		= "progressbar";
		elem.style.width 	= width+"px";
		elem.innerHTML 		= percentage + '%';		
	});
	
	setTimeout("showUpload()", 750);
}