I currently have this code to check the website URL GET options for a specific ID, but whenever this code is run, I get a weird error: Uncaught TypeError: Undefined is not a function

Here is my code:

<script language=JavaScript>

    var familyid = id=8978566;

    var corporateid = id=8978565;



    if(window.location.indexOf(familyid) === -1)

       {

        document.write(Family ID not found);

       }



</script>

It would be awesome if i could get some guidance on this issue... I couldn't find similar issues using the .indexOf() function