'Background color of the page when an alert is showing

I currently have the following code that makes a prompt show up when trying to access a page

    <script>
var password = "1234";
if(prompt("Enter password:", "") !== password) window.location = "/";
</script>

What I want to know is if there is a way to change the background color of the page while the prompt is showing up:

javascript

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Solution	Source