iPad Safari Development toolbar

You can use this little trick to enable Firebug Lite or any other debugging tool built into a bookmarklet, works quite well actually!

http://www.blog.cordslatton.com/2010/11/debugging-ios-mobile-safari-ipad-iphone/

On the ipad go to Settings > Safari > Advanced and activate the Web Inspector.

Connect your ipad with your computer.

On your computer open Safari, enable the developer tools in the settings. check the above menu for the tab Developer and find your iPad there.

Full control via console from your desktop machine over the iOS Safari and you're done!

PS: This works exact the same way with the iPhone as well..

There is no developer toolbar for Safari iPad, but you could definitely use something like firebug lite to do most of what you want! Just add the bookmarklet to your bookmarks, and then load it while you're looking at your page.

Your other option is Weinre, a remote debugger and part of the PhoneGap project. Essentially, it lets you run an interface similar to the Chrome document inspector on your desktop machine, that manipulates the document on your iPad or iPhone. The commenter below brought my attention to this awesome tool a year ago, but since then the project's URL has changed so I'm adding it here.

FirebugLite does have some issues with rendering speed and dealing with JavaScript, and it additionally doesn't scale its fonts very well. For these reasons, Weinre is definitely a more powerful tool - but also harder to start using.