SO - 18185794

by Arun P Johny

HTML

<input type="password" id="Password" tabindex="2" class="nice-textbox">
<input id="PasswordChk" type="checkbox" disabled="disabled"/>

JavaScript

$('#Password').on("keyup", function () {
    var password = $.trim($(this).val());    
    $('#PasswordChk').prop("checked", password.length > 0);
});