Shell CGI + Javascript

#!/bin/bash

echo "Content-type: text/html; charset=utf-8; application/x-javascript"
echo
echo

var=123

if [ -n "$var" ]
then
    cat <<-FIM
    <html>
    <head>
    <script type='text/javascript'>
        function mostraMensagem() {
            window.alert('O valor é: "$var"');
        }
    </script>
    </head>
    <body onload="mostraMensagem();">&nbsp;</body>
    </html>
    FIM

    exit 1
fi

exit 0