Activate Web Inspector on Your iPhone or Other iOS Device
The Web Inspector is disabled by default since most iPhone users have no use for it. However, if you’re a developer or you’re curious, you can activate it in a few short steps. Here’s how:
Open the iPhone Settings menu. On an iPhone with an early version of iOS, access the Debug Console through Settings > Safari > Developer > Debug Console. When Safari on the iPhone detects CSS, HTML, and JavaScript errors, details of each display in the debugger. Scroll down and tap Safari to open the screen that contains everything related to the Safari web browser on your iPhone, iPad, or iPod touch. Scroll to the bottom of the page and select Advanced. Move the Web Inspector toggle switch to the On position.
Connect Your iOS Device to Safari on a Mac
To use the Web Inspector, connect your iPhone or another iOS device to a Mac that has the Safari web browser and enable the Develop menu.
With Safari open, select Safari from the menu bar and choose Preferences. Select the Advanced tab. Select the Show Develop menu in menu bar check box and close the settings window. From the Safari menu bar, select Develop and choose the name of your attached iOS device, then select the URL that appears under Safari to open the debug console for that site. After you connect your device, use your Mac to inspect the website you want to debug and have it open in the Safari mobile browser.
What Is Web Inspector?
Web developers use Web Inspector to modify, debug, and optimize websites on Macs and iOS devices. With Web Inspector open, developers can inspect the resources on a web page. The Web Inspector window contains editable HTML and notes regarding the styles and layers of the web page in a separate panel.
Before iOS 6, the iPhone Safari web browser had a built-in Debug Console that developers used to find web page defects. Recent versions of iOS use Web Inspector instead.
With Safari 9 and OS X Mavericks (10.9), Apple introduced Responsive Design Mode in Web Inspector. Developers use this built-in simulator to preview how web pages scale to different screen sizes, resolutions, and orientations.