Safari has an interesting set of options for debugging web pages. You just have to turn it on. From the Teminal, type the following:

defaults write com.apple.Safari IncludeDebugMenu 1

You can also turn it on for Windows by adding the following to your Preferences.plist (C:\Documents and Settings\USERNAME\Application Data\Apple Computer\Safari\Preferences.plist ) file:

<key>IncludeDebugMenu</key>
<true/>

For more info, check the Apple support documentation.