Problem with a small number of sites

Safari is my primary browser, and would be my only browser if I weren't having this problem.

There are 2 sites that I use with which Safari doesn't seem to play nice. In both cases, Safari can load the site, but a particular functionality is broken. In both cases, the sites seem to be trying to load a script, but they get hung up and no input can be entered.

I have tried these sites on my MacBook Pro and MacBook Air, with the same results. Unfortunately, the sites work fine in Windows/IE (one of them works on Mac/Chrome, the other does not).

Thanks in advance for any suggestions.