I’ve written a simple script that you can find here to get you started. Copy and paste it into the “Scripts” section of your page, and set “Placement” to “Head”:
You’ll notice there are a couple of values that you’ll probably need to change, the first is the URL param that you’ll be looking for (in the script it’s “utm_keyword”). The second is the ID you’re going to give a block of text on the page (it’s “keyword” in the script).
Open the text editor for the block of text you want to manipulate. Now you’ll need to switch to Source view for this (there should be a button called “Source”). Wrap the text that you want to change in a tag like this:
Welcome to our page about \<span id="keyword"\>cars\</span\>
Now the word “cars” will be replaced by whatever value you pass into “utm_keyword” in the URL. I’ve set up a demo page that you can see here:
_ NOTE: This solution may not work for an adwords quality score because the adwords bot won’t actually see the replaced text and will always get the default text (which is “dinosaurs” in my example above)._