Keypress Validation ALLOW CHARACTERS: a..z A..Z 0..9 - _ . , @ Reference keycode table: http://www.cambiaresearch.com/articles/15/javascript-char-codes-key-codes

CheckKeypress.js

$('input').bind('keypress', function(e) {// Kami.2013.12.24.10:57 Allow only letters, numbers, and @ , . - _
			var allowedCode = [8, 13, 32, 44, 45, 46, 95];
			var charCode = (e.charCode) ? e.charCode : ((e.keyCode) ? e.keyCode :
				  ((e.which) ? e.which : 0));
			 if (charCode > 31 && (charCode < 64 || charCode > 90) &&
				(charCode < 97 || charCode > 122) &&
				(charCode < 48 || charCode > 57) &&
				(allowedCode.indexOf(charCode) == -1)) {
				e.preventDefault();
				$('.alert-box.onerror').html('<h3>ALLOW CHARACTERS: a..z A..Z 0..9 - _ . , @</h3>').fadeIn();
				return false;
			 }
		  });