How to add Dynamic Text Replacement (DTR) to squarespace site?

I want to dynamically replace text on my landing page based on the Google Ad search string. For instance, if the string includes, "Texas," then I'd like the landing page to read, "We love Texas!" I assume it's done with javascript on squarespace. Do you have an example and code block?

Javascript would be used for this, yes. Can you provide an example URL that would be coming into your landing page? In other words. Is Google going to be sending query string parameters to your landing page that can be used to key off of?

I am wondering if i squarespace can work with custom query paramters? such as, squarespacesiteurl.com/?user_id=23432 assuming this query parameter value would be coming in from a backend service. 

@Datajoint001

It just depends on what you are trying to accomplish. We don't have access to SS's backend so there is no way server side to interpret any custom query parameters and act on those. Client side Javascript can be used to act upon query parameters in a URL but that action is limited to what can be done client side.

We would need more detail on how you want to act upon the user_id.