gibi-bir metin kutusundan metni kaldırmak için nasıl

elseif($num_rows >= 1)
{
?>
    <script>
        document.getElementById("newid").value="";
    </script>
<?php
echo "<font color='Red'><b>$logid</b> Ligin name has already been taken, Please chose another Login name.</font>";
}

this code I am using through ajax but this is not working. newid id text box control id on php login page