How to Activate the iPhone Debug Console

Prior to iOS 6, the iPhone's Safari web browser had a built-in Debug Console that could be used by developers to track down webpage defects. It's accessible through Settings > Safari > Developer > Debug Console.

Whenever CSS, HTML, and JavaScript errors are detected, details of each are displayed in the debugger.

However, more recent versions of iOS use what's called Web Inspector, but it's not accessible through Safari on the mobile device. Instead, you have to connect it to your computer and then open Web Inspector through the desktop Safari program.

Important: Accessing Web Inspector through USB is only available on Mac computers. If you're on Windows, try the method described in this Stack Overflow post.

The Web Inspector is disabled by default since most everyday iPhone users have no use for it. However, it can be activated in just a few short steps.

The very first step is to tap the Settings icon from the home screen.

Your iPhone Settings menu should now be displayed with several items listed. Scroll down until you find one called Safari, and then tap on it.

This will open everything related to the Safari web browser on your iPhone, iPad or iPod touch. 

Scroll to the very bottom of this page until you find an Advanced menu. Open that menu for some other options.

In Safari's Advanced screen of the Settings app is an option called Web Inspector. It's most likely disabled since it is by default. Tap the toggle button to its right to enable the Web Inspector.

To use the Web Inspector requires that your device is plugged in to a computer that's running the Safari web browser. Plug your phone or tablet into the computer and open Safari from your computer.

With Safari open, do the following:

1. Click the settings gear icon at the top right of the browser.
2. Choose Preferences....
3. From the Advanced tab, select the box next to Show Develop menu in menu bar.
4. Exit the settings window.
5. Open the Develop > Show Web Inspector menu item.

Note: If the menu bar isn't currently showing in Safari on your computer, return to Step 1 but then choose Show Menu Bar from that drop-down menu.