With iOS 6, Apple introduced a new Safari feature called “Web Inspector” for debugging web applications on iOS devices such as the iPad, iPhone or iPod touch. This feature can help anybody, especially web developers, find and correct problems with websites. Here is how to use this feature:
Turn on Web Inspector on your iDevice by tapping Settings > Safari > Advanced and toggle on Web Inspector.
After you’ve turned on Web Inspector, you need to connect your device to your computer (Mac only, PC computers do not support this feature). Proceed to launch Safari on your Mac computer. First ensure you have developer tools in Safari turned on. If you can see “Develop” in the menu bar, then it is turned on. If you need to turn Develop Menu on, click “Safari > Preferences > Advanced” and check the “Show Develop menu in menu bar” check-box.