Accessing userscript variables from the Google Chrome console

Question

For debugging purposes, is it possible to access userscript variables from the console in Google Chrome?

Answer 1

Suppose you had a Chrome userscript with this code:

var userscriptVar = "I'm a global variable, userscript context.";
window.var2       = "I'm a window.scope variable, userscript context.";

console.log ("Hello from the userscript.");

To access these userscript variables:

1. Determine the userscript's ID. You can see it on the extensions page (chrome://extensions/):

   

2. Switch to the script's context by clicking on the context menu at the bottom of the console:

   

   Note that the id (pfnbaeafniclcjhfkndoploalomdmgkc) is the same as that listed on the extensions page.

3. Now you will immediately be able to see and change the window-scoped variable (var2), but you can't see the userscript's global (userscriptVar) because the script-instance has long since finished and disappeared. :

   

4. To access and change userscript variables, while the script is still active, set a breakpoint in the script and use the debugger. See this answer for how to do that.

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5. With the userscript paused at a suitable breakpoint, you can see, but not change the global values, from the console.

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6. But you can change the value from the debugger:

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