Javascript RegExp
by ChrisStanyon
HTML
<input type="text" id="user" />
<button id="click">Click</button>
<div id="response"></div>
JavaScript
$('#click').click(function() {
usr = $('#user').val();
regex = new RegExp("^[a-z]+\\d{3}$");
$('#response').text(regex.test(usr));
})