Modify validation script to set focus on field in tabbed form

I'm using the script at bottom to validate a particular field. The problem is: I don't know how to get to focus on a field in the first tab of a tabbed form.

I'm trying to get there with this -- setTimeout( function() { $( '#tabs-0' ).focus() }, 500 );

but it doesn't work.

Here's how the .NET form begins...

<div class="divider">&nbsp;</div><table id="tblControls" border="0" cellpadding="2"><tr id="ctl00_ctl00_row1_cntrlID_15290">
      <script type="text/javascript" language="javascript"> $(document).ready(function(){ $("#tabbed").tabs(); }); </script> <div id="tabbed"> <ul> <li><a href="#tabs-0">Tab One</a></li> <li><a href="#tabs-1">End Tabs</a></li> <li><a href="#tabs-2">Medical Before Enlistment</a></li> </ul><div id="tabs-0" class="tabs"><table><tr></td>
</tr>
...
<div id="tabs-0" class="tabs">

Here's the field I need to set focus to if the date format is incorrect:

...
<input name="ctl00$ctl00$cntrlID_10724" type="text" value="Dec 11, 1914" id="ctl00_ctl00_cntrlID_10724" class="k-textbox" onkeypress="if(typeof(CheckForFormSubmit)==&#39;function&#39;){ return CheckForFormSubmit(event);}" style="width:100px;" />

Here's the script I'm validating with, which includes the focus problem:

function validate() {
 
  var theForm = document.forms['aspnetForm'];
  if (!theForm) {
    theForm = document.aspnetForm;
  }
  var emptyString = /^\s*$/ ;
  var dmmyyyy = /^((([1-9]...$/
  var ddmmyyyy = /^...$/
  var mmyyyy = /^...$/
  var yyyy = /^(17|18|19|20)\d{2}$/

  if(!emptyString.test(theForm.ctl00$ctl00$cntrlID_10724.value) && !dmmyyyy.test(theForm.ctl00$ctl00$cntrlID_10724.value) && !ddmmyyyy.test(theForm.ctl00$ctl00$cntrlID_10724.value) && !mmyyyy.test(theForm.ctl00$ctl00$cntrlID_10724.value) && !yyyy.test(theForm.ctl00$ctl00$cntrlID_10724.value))
  {
      alert("Date appears invalid. Accepted formats include: \n\n d\/mm\/yyyy, dd\/mm\/yyyy, mm\/yyyy and yyyy");
 
  //THIS IS WHERE I NEED TO FOCUS ON THE PROPER TAB
    setTimeout( function() { $( '#tabs-0' ).focus() }, 500 );    //THIS DOESN'T WORK
    theForm.ctl00$ctl00$cntrlID_10724.focus();  //THIS WORKS IF I'M ALREADY IN THE ACTIVE TAB
  }

   else {
 
    ClickOnce_ctl00_ctl00_btnSubmit();

  }

 }

Who can help?