How can I solve a redirect by script?

There are many ways to implement a redirect, be it internal or external. If, on the other hand, neither the inclusion of a code, in the header, footer or as a body onload is possible and, in addition, jQuery must also be dispensed with, the solutions become fewer.

Below is a simple script, which must be inserted within the body.

<script language="javascript" type="text/javascript">
          
  setTimeout(function()
  {window.open('https://www.hiergehteszurgewuenschtenwebseite.de', '_blank');
             } , 1000);
  
         
</script>