A website I wish to tweak is using window.location in order to redirect specific users to a blocking page. That website is doing it in plain <script> tag, so it is impossible to bypass it by overriding the onload event using document.body.setAttribute('onload','');.
Is there another way to inject my code to the page without using Firefox extensions such as NoScript?
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script type="text/javascript">
if (1) window.location="http://example.net"
</script>
</head>
<body></body>
</html>