SO fiddle

Test Fiddle mainly for SO Questions

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/overcast/jquery-ui.css">

JavaScript

var regExpression=new RegExp("^([a-zA-Z0-9_\\-\\.]+)$");

alert (regExpression.test("11aa"));