How to get websites javascript value into python variable?

Question

I need to get the value of JavaScript on a website into my python script.

<script>
    window['itemstorage'] = {
        itemid: 102416,
    };
</script>

So I need that itemid into my python script so I can perform a http get request.

My script already returns the whole html script but thats where I'm stuck would appreciate help. Thank you!

I tried to find this on other questions but weren't able to connect the to my script.