您需要最新的苹果浏览器。在这里：

http://nightly.webkit.org

I am trying to debug a web application under ios 8 beta on a simulator. Running the latest version of safari (Version 7.0.6) and Xcode, but all I am able to see is "No Inspectable Applications" in safari.

Any suggestions ?

You need the latest nightly build of Safari. Get it here:

http://nightly.webkit.org