Web Development

How to Inspect Interactions in the Browser

February 14, 2023

Written By Sami Jaber

The other day, I tried to debug this autocomplete list’s broken styles:

A screenshot of autocomplete broken styles.

But as many of you have experienced, when you click in your console, that moves focus out of your webpage, and the popover goes away! In this case, I can’t even right-click the popover to click Inspect Element:

I looked around and found two wonderful solutions to this problem in Chromium browsers.

Solution #1: Emulate Focus Page

Open your console, press Cmd+Shift+p to open the command palette, and search for Show Rendering :

A screenshot of a search in the command palette in chrome devtools for "show rendering".

This opens a Rendering tab, where you can enable Emulate a focused page.

a screenshot of the Rendering pane inside devtools showing "emulate a focused page" checkbox selected.

This will preserve focus when you click around in your console.

Solution #2: Break On Subtree Modifications

This one is less practical for this particular example, but can be really useful in situations that have nothing to do with focus. You can COMPLETELY pause JS and enter debugging mode whenever a portion of the HTML has any modifications happen to it!

You start by adding a breakpoint to the subset you care about. In this case, I’ll choose the entire code editor area:

A screenshot of devtools element pane with the sub menu showing and highlighting "break on".

And now, this is what happens when I type a character in the editor:

As you can tell, this requires stepping a lot in the debugger. I prefer solution #1 to preserve focus, but I can see myself using the Break On feature for other complex interactions, especially if I want to jump into the JS code!

Conclusion

Hopefully, you’ll be able to use these tools the next time you want to debug your client-side UIs. If you know of any other cool browser dev tools, share them with us!