intermittent white pages in safari and others - fix?

I have a macbook air 10.7.5 about three years old and a new macbook running 10.8 . A few months ago *some* pages on safari started to load as blank white pages, and would some times be better on firefox. One example site is schwab.com. Sometimes this can be fixed by re-loading, sometimes not.

I was very surprised to see that my new macbook running 10.8 has the same issues, and generally, switching to firefox does *not* solve the problems.

I tried resetting plist of safari and so forth, no help.

I'm thinking that there is something like some uses of flash prevent the page to load ....??? This might be why some troubles are sometimes common to safari and firefox. I thought this should go in

This is a common problem, I 've seen descriptions of this on the web elsewhere, and another 10.7 user down the hall has the same problem. Any fixes or diagnostic suggestions would be appreciated.

-BTP