function returnDocument() {
	var file_name = document.location.href;
	var end = (file_name.indexOf("?") == -1) ? file_name.length : file_name.indexOf("?");
	return file_name.substring(file_name.lastIndexOf("/")+1, end);
}

$(document).ready(function(){ 
	$('#navigation a[href='+returnDocument()+']').addClass("active");
});