Bypassing Google "URL Swapping" in Firefox on Mac

Problem: Users on my wifi network can't click on ad links in Google Search results because those links redirect to the ad.doubleclick.net domain, which is blocked by my Pi-hole. The user ends up on a page with this error message:

Unable to connect. An error occurred during a connection to ad.doubleclick.net. 

This happens on Firefox (as of the time of this post, January 2025) because Google is doing something a little bit sneaky: If you mouse over a hyperlink in a sponsored ad in a set of Google search results, it appears to be a normal hyperlink. However, as soon as you click on that link, Google swaps out the target of that link to be a different one than the one that was displayed -- and that's where the link ends up taking you.

(In more technical terms: Google appears to be using JavaScript's onClick event to cancel the navigation to the original href; then replaces the original href with the new href; and then proceeds to navigate to that new destination.)

For example, one of the results when I searched Google just now for "new wireless service" was https://www.verizon.com/plans/unlimited. However, clicking on that link actually navigated me to an URL starting with https://ad.doubleclick.net/searchads/link/click?lid=... . 

You can actually see the swapped-in hyperlink by using the browser's back button to return to the Google search results page, and mousing over the clicked hyperlink again. You'll see that preview of the destination URL for that same link has now changed! (The same happens if you right-click on the target link, then cancel the right-click context menu, and hover over the link again.)

My family members from time to time actually want to click on a sponsored Google search result, and have the navigation work properly. However, I don't want to whitelist the entire "ad.doubleclick.net" domain at my Pi-hole, since that would likely result in a lot more distracting ads being rendered as we use the web. 

I searched for a Firefox add-on which would prevent hyperlink URL destinations being changed from the preview URL that was shown prior to clicking on them, but couldn't find one that seemed trustworthy. 

(I do already run EFF's Privacy Badger add-on, which purports to include this particular functionality; but for whatever reason, it isn't working for me in Firefox as of the time of this post. Possibly Google has recently updated the mechanism that they use to perform their URL-swapping in Firefox; and Privacy Badger hasn't yet been correspondingly updated.)

Workaround / Solution

To my surprise, Google doesn't seem to perform their URL replacement when the search link is activated by the Return key, instead of by a click! Therefore, a crude-but-effective workaround is as follows, when looking at a page of Google search results:

1. Hit the Tab key until the desired link has the focus. 
• (Alternatively, double-click a word of text near the target link to select it; then press Tab and/or Shift-Tab from there until the desired link has the focus.)
2. Press Return to activate the link.

This workaround does have the advantage of not needing any browser add-on to work!

When doing this, Google (apparently) doesn't have any JavaScript in place to hijack the link destination; the client browser navigates directly to the actual URL shown in the browser's preview, without being redirected through ad.doubleclick.net (or any other domain).