hello ranjith
here is my explanation
<asp:textbox onkeyup="return getbinded();" xmlns:asp="#unknown" ></textbox>
javascript function
<script type="text/javascript">
function getbinded()
{
if(document.getelementbyid('txtboxid').text.length>0)
{
document.getelementbyid('labelid').innertext='yes'
}
else
{
document.getelementbyid('labelid').innertext='';
}
}
window.onload=getbinded()
</script>
hope this will help you :)