Editing a textbox in a web page

I'm currently developing a client for a web-based game. In this game I wish to edit the content of a text box displayed on the website, but can't think of any automated way to do it.

I can search for the text I wish to edit in the source file, but can't think of a way to make the edit except copying the new string to clipboard and having to paste it manually. I'm usually pretty good with problem solving such as this, but I seem to have hit a block.

Any help would be greatly appreciated.

 

From a textbox or textarea?

Because I have the found the way to do this in a textbox.

 

Well, considering he said "text box", I'd say he means text box. Lol.

 

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