Function to detect whether the current request is from XMLHTTPREQUEST

is_xhr.php

<?
	/*
	 * Detect whether the current query is ajax
	 *
	 * TODO: check if this works across browsers and ajax libraries
	 */
	function is_xhr()
	{
		if(isset($_SERVER['HTTP_X_REQUESTED_WITH']) &&
		strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest')
		{
			return true;
		}
		else	
		{
			return false;
		}
	}
?>