Joannesalfa if you just want a donation button in game you don't even need to integrate <div></div>. All you have to do is:
1. Get or make a donate button image, and place it in your game.
2. Give your game the "Browser" object, then the mouse, and or touch object.
3. Go back to your paypal account, an create a new donation button.
4. Then click on your paypal buttons view code tab, and copy the email code.
5. In Construct 2 go to your event sheet, and add:
+mouse -> on object clicked (donate button image)
-browser-> Open URL in new window
Then just paste in your email code.
And you should get something like this:
Example Feel free to donate <img src="smileys/smiley4.gif" border="0" align="middle">
Here is a .capx