php and java script focus()

[Rina]

Hi all.
I try to place focus in a textfield (Sup_no) after the page get an error message. I try coding it in Javascript along in php script.
However, the code below does not function.
I hope anyone here can help me correcting the code below.
Thanks in advance.

    <?php
    $err = $_GET['msg'];
    if ($err=='error'){
        echo "<br>";
        echo "<center><font face=verdana size=2 color=red><b>Supplier No already existed in database, please key in new Supplier No</b><center>";
        echo "<script language='JavaScript'>";
        echo "document.form2.Sup_no.focus()";
        echo "return false";
        echo "</script>";
    }
     ?>