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.