Simple Javascript function to grab the parameter in the url and send an alert.

getURLvars.js

<script type="text/javascript">
$(document).ready(function(){
	$.urlParam = function(name){
		var results = new RegExp('[\\?&]' + name + '=([^&#]*)').exec(window.location.href);
		return results[1] || 0;
	}
	// example.com?param1=name&param2=&id=6
	alert($.urlParam('param1')); // name
	alert($.urlParam('question')); // name
	alert(decodeURIComponent($.urlParam('question')));
	$.urlParam('id');        // 6
	$.urlParam('param2');   // null
	 
	//example params with spaces
	http://www.jquery4u.com?city=Gold Coast
	console.log($.urlParam('city'));
	//output: Gold%20Coast
	 
	console.log(decodeURIComponent($.urlParam('city')));
	//output: Gold Coast
});
</script>

Updated to use jquery version and include some example alerts.