// ajax xmlHttpRequest

function makeAjaxRequest() {
	var httpRequest;

	if (window.XMLHttpRequest) 
	{ 
		
		// Mozilla, Safari, ...
		httpRequest = new XMLHttpRequest();
		if (httpRequest.overrideMimeType) 
		{
			httpRequest.overrideMimeType('text/xml');
		}
		
	} 
	else if (window.ActiveXObject) 
	{ 
		// IE
		try 
		{
			httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
		} 
		catch (err1) 
		{
			try 
			{
				httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
			} 
			catch (err2) 
			{
			}
		}
	}

	if (!httpRequest) 
	{
		alert('Giving up : Cannot create an XMLHTTP instance');
		return false;
	}
	
	return httpRequest;
}