Safari 5 vs. Safari 4 : Are there any compatibility differences?

I recently obtained a Mac so I could test our sites on Safari and Firefox for Mac OS.

Now that Safari 5 is out, I'm not sure what I should do about upgrading. I presume what works on Safari 5 works on Safari 4, but I can't be sure, and vice versa. So, I don't know if I should upgrade and test on Safari 5 or keep on with Safari 4.

Are ther开发者_如何学运维e any major differences between these two version in terms of CSS (2.1) handling or JavaScript? When do you think the majority of people will have Safari 5 instead of 4?

All thoughts appreciated.

---

You need virtual machines! :D

With virtual machines you can install multiple OS, configure what will be the hardware of the virtual machine and be able to have different software from one virtual machine to another.

Example: You could have a Mac OS 10.6 with Safari 5 in a virtual machine and have Mac OS 10.6 with Safari 4 in a virtual machine.

Virtual machines for Mac OS:

• http://www.parallels.com/products/desktop/
• http://www.vmware.com/virtualization/

---

It might be worth your while visiting: http://michelf.com/projects/multi-safari/, which offers a number of downloadable files to allow multiple versions of Safari to co-exist on the same system (albeit some versions are limited to pre-, or post-, Leopard).

I can't, I'm afraid, answer the question you ask "...are there any compatibility differences?" with real certainty; I'd assume there will be differences between versions (old bugs will likely be corrected, and some new bugs created, not to mention increased up-take of standards) otherwise there'd be no point to releasing a new version. There's certainly increased implementation of html 5, but whether that's new to Safari or to the Webkit engine, I don't know. If it's the Webkit engine the changes should be reflected in any old, default, installation of Safari (since Safari uses, so far as I can tell, the Webkit engine built into/supplied with the OS itself).