Checking different Browser Compatibility in single browser

I want to check different cross browser compatibility in a s开发者_运维百科ingle browser.Is there any package to check those browser compatibility,because I am using Low specifiaction System.so i cannot install different browsers.It takes time to load.Currently I am using Mozilla Firefox 4.

Any Idea!!!!

To test different IE versions, you can use IETester. For Firefox, if you don't want to install multiple versions, you can use Pocket Firefox ports that you can run from a usb drive

No need to install a tool locally rather use an online resource like:

Check Browser Compatibility

If you just need to check that it looks right, browsershots.org

I guess Lunascape the triple-engine browser (trident/gecko/webkit) is probably what you are looking for.