$(function(){

	$('input[name="username"]').keydown(function(key){
		if ( jQuery.inArray(key.keyCode, [8,9,37,39,48,49,50,51,52,53,54,55,56,57,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90]) == -1 || key.shiftKey ){
			return false;
		}
	});

});