In the image click I write code for invoke java like this

```
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
        <title>New Page 1</title>
    </head>
    <body>
        <table cellpadding="0" cellspacing="0" width="311">
            <tr>
                <td height="14">
                    <img onclick ="SignIn();" border="0" src="../images/Sign_In.gif" width="80" height="28">
                </td>
            </tr>
        </table>
        <script type="text/javascript" language="JavaScript">
            function SignIn(){
                alert();
            }
        </script>
    </body>
</html>

```

The above code is working fine in Internet Explorer, but not in FireFox. What is the problem?