Focus to an Text Input

Currently I am taking a value from a text box, validating that it is a known value(only certain values can be entered), then if it is not within the select box I add the value to the select box, then whipe out the text value.  I have tried to give the focus back to the text box after all of this, but it never happens.  here is the code.

<script language="Javascript">
var uicstr;
function popUicArray(thestr)
{
  uicstr = thestr;
}
function findUic(theuic)
{
 if(theuic != "")
 {
   var found = uicstr.indexOf(theuic);
  // alert(uicstr + ' ' + theuic);
   if(notinfinal(theuic))
    {
     if(found != -1)
     {
       CPOCommandForm.uic.length++;
       CPOCommandForm.uic[CPOCommandForm.uic.length-1].text = theuic;
      CPOCommandForm.entryuic.value = "";
       CPOCommandForm.entryuic.focus();  
     }
     else
     {
     alert("That uic could not be found. Please try again.");
     }
   }
 }
 else
     CPOCommandForm.entryuic.focus();

CPOCommandForm.entryuic.focus();  
}
function notinfinal(theuic)
{
   for (var i=0; i < CPOCommandForm.uic.options.length; i++)
   {

    if(CPOCommandForm.uic.options[i].text == theuic)
    {
     //found that uic in the list so return false
      return false;
    }
  }
   //  was not in the list
   return true;
}
</script>

The uicstr is populated earlier. Here is how the text input calls the function:
<td valign="top" align="left">
  <input type="text" name="entryuic" onchange="findUic(this.value)"   size="5" maxlength="5">
</td>
 <td>
<select name="uic" style="height: 150px" size="5" onDblClick="removeSelection(CPOCommandForm.uic.selectedIndex)"></select></td>

Any Ideas?

Thanks
Ben Switzer