If it is ran on iOS, it will freeze the phone until it eventually crashes and reboot.
If ran on Windows, Mac OS, or Android, the webpage may cause the browser to freeze or hang.
If ran on the Nintendo 3DS browser, it will open numerous new tabs, which will cause the device to lag or freeze. This also disables you to go back to previous tabs, as the Nintendo 3DS browser auto switches to the latest opened tab. The browser on New Nintendo 3DS systems is immune, as it just tries to load the page forever.