Not necessarily. Not all browsers alert you for that. He could check the Error console, which may not be accessible in certain browsers. I'm afraid he may be using Internet Explorer 6, which is known to have many problems, and isn't supported by barely any websites anymore. If he is using Firefox, Chrome, Safari, or Opera, then he should try clearing his cache, and then checking if his add-ons and extensions are up-to-date. If he is using Internet Explorer 7 or above, he should try restarting his browser and checking for updates. Then we will see from there.