Modern browsers offer the ability to edit the HTML source of a page while viewing it; for instance, on Firefox, with right click - inspect element - right click on the line highlighted in blue - edit as HTML, I can modify any text appearing in any web page.

What happens if I alter the text of a click-through license in this way before clicking "OK"? One could argue that this is equivalent to striking out a clause from a contract before signing it; however, the other party typically has no way to figure out that it has happened, because it is a modification that I make only on my web browser, and the text of the page is usually not sent back to the server together with the button click.

What would be the legal validity of this behaviour? Suppose, for instance, that I get a witness to confirm that I clicked "I agree" on a modified page and not on the original one. You may assume that all parties are in the US, for simplicity.

  • 3
    If this could hold up in a court, I'd sign up for Facebook again and modify the terms to say "Facebook agrees to pay me $5 per day for each view of my posted content", sit back, and retire. Part of a contract is a "meeting of the minds", which you would not be able to demonstrate on behalf of the other party. Contract law would fall apart if things like this could happen...
    – Ron Beyer
    Sep 18, 2018 at 19:10
  • "Modern browsers offer the ability to edit the HTML source of a page while viewing it" - Traditional paper contracts also offer you this ability; you can cross out a part you disagree with or add your own terms. Of course in order to do this both parties must agree to the contract changes.
    – Brandin
    Sep 20, 2018 at 7:01

2 Answers 2


What would be the legal validity of this behaviour?

Your changes to the browser source of the website contract or license of Terms of Service (TOS) - essentially a "click-wrap" license - before agreeing to it means nothing in a legal sense, other than to void the contract.

The other party (the website) can't possibly agree to those contract changes without them being submitted as contractual changes and agreeing to them, if they did agree to them. That's basic contract law.

That website TOS probably has a clause that says that if you don't agree to the TOS in full, as written, without modifications, you can't use the website. And the TOS may also say that they reserve the right to prevent you from using the site by closing your account or even blocking your access.

Your "witness" to the contract changes is meaningless, as your witness is not a party to the contract. And any witness to the fact that you have changed the terms of the TOS before agreeing to it would work against you in a civil proceeding as proof of your attempt at modifying the contract.


I think that you have not accepted the offer made in the website page in the first place. There is no "unequivocal acceptance" of the offer made by the website.

That means there is no contract at all. It was never formed in the first place. That's cause there is no consensus ad idem.

Assuming your friend gave evidence for you, and says as indicated above, you'd be toasted all the more.

Just thinking this through a bit more...

So, you wouldn't be licensed to use the website. Every page you looked at would be a copyright infringement. I hear there are some pretty nasty statutory damages available in the US...

But then there could be a contract implied by your conduct (ie your use of the website). That contract might be the same terms as those set out in writing on the web page in the first place.

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