SO jQuery Fiddle

Test Fiddle mainly for SO Questions jQuery 1.4.3, UI 1.8.5

by Nick Craver

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.5/themes/ui-lightness/jquery-ui.css">
<p>Lock Date?: <input type="checkbox" id="chkBox" /></p>
<p>Date: <input type="text" id="txtDate" /></p>
<p>Select: <select id="someSelect"><option>Test</option><option>Test2</option></select></p>

JavaScript

$("#txtDate").datepicker();

$("#chkBox").change(function() {
  $("#txtDate").attr("readonly", this.checked)
               .datepicker(this.checked ? "disable" : "enable");
  $("#someSelect").attr("disabled", this.checked);
});