I have this problem too.
One solution that seems to work best for me, is navigating the page by using the "tab" button on your keyboard. By doing this you can easily be able to type in your username and password without having to click on the page. Then when you're all done, just hit "enter".
Hope this helped c:
The site isn't being hijakced, this is just how the creators get payed so they can keep the game up. Just be careful when navigating the website. And if any tab does pop up, close out of it as quick as possible.