Blocked a frame with origin "null" from accessing a cross-origin frame. - Chrome

Help, I want to create a Site where you can visit what an user is doing in a Window...

My code:

<script>
    google = window.open("https://www.google.com/")
    
    function getLocation() {
         console.log(google.location.href)
    }
</script>
<button onclick="getLocation()">Get Location</button>

But I always get the output:

main.html:5 Uncaught DOMException: Blocked a frame with origin "null" from accessing a cross-origin frame.
at getLocation (file:///C:/Users/*****/Desktop/main.html:5:42)
at HTMLButtonElement.onclick (file:///C:/Users/*****/Desktop/main.html:8:37)