javascript modify script before execution

Question

I would like to modify a piece of javascript that gets loaded by a webpage before that code actually is executed. I know where the line of code I want to modify is, and I can use the browser debugger to set a breakpoint just before that line, however, once the execution is paused I'm unable to modify the script code.

Does anyone know how to achieve this?

PS: Please note that all the rest of the script can remain identical to the original, and I don't want to block all javascript execution, just change a single (or a few) line before my browser runs it.

@AvivLo temporarily I suppose? I don't have control over the server that is providing me the script, so I am only interested in local changes in the browser in the current "loading" of the page. — ClonedOne
– ClonedOne, Commented Apr 22, 2020 at 4:06
You will probably have to write another script that changes the script that you want to modify before you actually load it. This is just a theory. — Algo7
– Algo7, Commented Apr 22, 2020 at 11:37

ParthianShotgun · Accepted Answer · 2020-04-21 16:10:11Z

1

This is tantamount to override, and there is already a question that answer that

Override Javascript file in chrome

Personally I would go with the local override option as described here

answered Apr 21, 2020 at 16:10

ParthianShotgun

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ClonedOne Over a year ago

Interesting, I hoped there would be an easier, and less browser-specific solution, but this is a good start. Thank you!

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