website written in HTML using iWeb doesn't show up correctly in different browsers

I have a question regarding how to make the same website appear consistently in different browsers on different platforms.

The following is a website that I made for my professor: http://youlab.wustl.edu/Home.html. The site itself was made using iWeb while the drop down menu was manually inserted using an external HTML code provider (SoThink DHTML).

While Firefox displays the site correctly, all the other browsers had some sort of problem displaying the site.

• Internet Explorer: none of the links work
• Chrome &开发者_JS百科 Safari: the drop down menu is shifted all the way to the left, and were not clickable since it disappeared when the mouse moved towards it.

The movie on 1 page doesn't work either.

Could someone tell me what is wrong and how to fix the problem?

Here's your answer

http://en.wikipedia.org/wiki/Cross-browser