Restrict the user to only being able to type a digit

User can only enter digits in input text

	$('input').bind('keypress', function (event) {
		var regex = new RegExp("[\d]"); 
	    var key = String.fromCharCode(!event.charCode ? event.which : event.charCode);
	    if (!regex.test(key)) {
	       event.preventDefault();
	       return false;
	    }
 	});