Editing in the Chrome debugger

Question

I came across this today, when I was playing around with someone else's website.

I realized I could attach a break-point in the debugger to some line of code before what I wanted to dynamically edit. And since break-points stay even after a reload of the page, I was able to edit the changes I wanted while paused at break-point and then continued to let the page load.

So as a quick work around, and if it works with your situation:

1. Add a break-point at an earlier point in the script
2. Reload page
3. Edit your changes into the code
4. CTRL + s (save changes)
5. Unpause the debugger

You can use the built-in JavaScript debugger in Chrome Developer Tools under the "Scripts" tab (in later versions it's the "Sources" tab), but changes you apply to the code are expressed only at the time when execution passes through them. That means changes to the code that is not running after the page loads will not have an effect. Unlike e.g. changes to the code residing in the mouseover handlers, which you can test on the fly.

There is a video from Google I/O 2010 event introducing other capabilities of Chrome Developer Tools.

You can use "Overrides" in Chrome to persist javascript changes between page loads, even where you aren't hosting the original source.

1. Create a folder under Developer Tools > Sources > Overrides
2. Chrome will ask for permission to the folder, click Allow
3. Edit the file in Sources>Page then save (ctrl-s). A purple dot will indicate the file is saved locally.

This is what you are looking for:

1.- Navigate to the Source tab and open the javascript file

2.- Edit the file, right-click it and a menu will appear: click Save and save it locally.

In order to view the diff or revert your changes, right-click and select the option Local Modifications... from the menu. You will see your changes diff with respect to the original file if you expand the timestamp shown.

More detailed info here: http://www.sitepoint.com/edit-source-files-in-chrome/

Pretty easy, go to the 'scripts' tab. And select the source file you want and double-click any line to edit it.

If its javascript that runs on a button click, then making the change under Sources>Sources (in the developer tools in chrome ) and pressing Ctrl +S to save, is enough. I do this all the time.

If you refresh the page, your javascript changes would be gone, but chrome will still remember your break points.