Hello, I need to create an extension, in which I change a parameter of an ID in HTML, (maxlenght), but only in a certain URL, is it possible?
Yes this is possible and it’s even a very basic use case for an extension.
Have a look at this tutorial about how to create a basic extension.
Then change the
document.querySelector() for doing so), then
element.setAttribute("maxlength",newMaxlength) to change the attribute value.