Response to: Set Focus on Textbox using Javascript

Revision 3
use this code in your Javascript text box field.

<script language="javascript" type="text/javascript">
        if (document.getElementById("Textbox1").value == "") {
            alert("Invalid date");
            document.getElementById('Textbox1').value = '__/__/____';
            document.getElementById("Textbox1").focus();
        }

It is working fine for me.