function decode_email( key, email ) {
    img = document.getElementById( "img_email" );
    img.style.display = "none";
    for (i = 0; i < email.length; i++) {
        charpos = key.indexOf( email.charAt( i ) );
        charpos = (charpos+1) % key.length;
        newchar = key.charAt( charpos );
        document.write( newchar );
    }
}