How do I checkout my blog in most browsers

(I know I should be able to find the answer by searching, but I must be failing on using the right search terms.)

I have two browsers installed on my PC and check out my blog on both of those. I’m wondering if there is a site or WP feature I can use to check the correctness of the html and its compatibility with other browsers. Some of my users have mentioned a problem with the display on their browser. Thanks for any help you can give in pointing me in the right direction.