function createRequestObject() {
	
	try {
	
		var browser = navigator.appName;
		var ajax;
		if(browser == "Microsoft Internet Explorer") {
			
			ajax = new ActiveXObject("Microsoft.XMLHTTP");
			
		} else {
			
			ajax = new XMLHttpRequest();
			
		}
		
		return ajax;
	
	} catch(e) {
		
		alert(e.message);
		
	}

}

function ProgressBar() {
	
	this.ajax = createRequestObject();
	this.url = 'progress.php?key=';
	this.self = this;
	this.key = document.getElementById('progress_key');
	this.container = document.getElementById('progress_container');
	this.bar = document.getElementById('progress_bar');
	
}

ProgressBar.prototype.show = function() {
	
	this.container.style.display = 'block';
	
}

ProgressBar.prototype.hide = function() {
	
	this.container.style.display = 'none';
	
}

ProgressBar.prototype.poll = function() {
	
	var a = this;
	closure = function() { 
		a.update();
	}; 	
	
	this.ajax.open('get', this.url+this.key);
	this.ajax.onreadystatechange = closure;
	this.ajax.send(null);

}


ProgressBar.prototype.update = function() {
	
	if(this.ajax.readyState == 4) {
	
		var result = eval('(' + this.ajax.responseText + ')');
		
		if(result.done != null) {
			
			/** We're done! **/
			
		} else {
			
			
			setTimeout(this.poll, 500);
			
		}
		
	}
	
}

ProgressBar.prototype.start = function() { 

	this.show();
	this.poll();
	
}	

function doSubmit() {
	
	progressBar = new ProgressBar();
	progressBar.start();
	
}