Question: On Windows I can use Utilu Firefox collection (there also ie collection on his site).

How can I use multiple browser versions to see how my website works in different versions of different browsers in OS X?

For example I want to install [browsers with biggest market share](https://en.wikipedia.org/wiki/Browser_market_share#Summary_table):

* Internet Explorer
* Firefox 3.6, latest and previous
* Google Chrome latest and previous
* Safari (any older versions possible)
* Opera

Answer: 
Firefox
-------

[Firefoxes](https://github.com/omgmog/install-all-firefox) is a shell scripts that will install all major versions of Firefox on OS X, and set up separate profiles so you can use them simultaneously. Currently it installs:

* Firefox 2.0.0.20
* Firefox 3.0.19
* Firefox 3.5.9
* Firefox 3.6.28
* Firefox 4.0.1
* Firefox 5.0.1
* Firefox 6.0.1
* Firefox 7.0.1
* Firefox 8.0.1
* Firefox 9.0.1
* Firefox 10.0.2
* Firefox 11.0
* Firefox Beta
* Firefox Aurora
* Firefox Nightly
* Firefox UX Nightly

You can set it up so it only installs the specific versions you want.

Optionally, the script can install Firebug for each version of Firefox too.

It will also set icons that contain the version number:

![](https://i.stack.imgur.com/FnlXM.png)

Safari
------

For Safari, check out [Multi-Safari](http://michelf.com/projects/multi-safari/).

Chrome/Chromium
---------------

For Chrome/Chromium, install any version you want, change the app name from `Chromium.app` to e.g. `Chromium 19.app` for clarity, then [disable auto-updates](http://dev.chromium.org/administrators/turning-off-auto-updates) for that version.

Opera
-----

Download old Opera versions here: <ftp://ftp.opera.com/pub/opera/mac/>

IE
--

Get VirtualBox and then run [this `ievms` script](https://github.com/xdissent/ievms). It will automatically download legal Windows images for testing purposes and set up virtual machines for every IE version you need.
While not actually on your machine, you can also use a web application like [BrowserShots.org](http://browsershots.org/) to deliver you screenshots of the page rendered in a multitude of browsers or something like [Adobe's BrowserLab](https://browserlab.adobe.com/en-us/index.html#).