Changing how URL parameters are appended to links based on destination

Question

My company is serving up PPC landing pages with Unbounce (on a subdomain), which then links back to our website. We're using the following code to append the AdWords gclid variable to outgoing links:

 $(document).ready(function() {var params = window.location.search.replace(/\+/g,'%20'); var button = $('a').each( function(i) {this.href = this.href + params;});});

The issue arises when the Gclid gets appended to a URL that already has a parameter (like our checkout forms). You end up with a URL that looks like this:

domain.com/checkout?EventID=15546?Gclid=jdkI324kd 

I'm wondering if there's a way to change the Glid's '?' to an '&' for certain URLs that already have parameters, while keeping the existing functionality of using the '?' for the others.

Thanks!

Edit: Seems like there's some redirection going on, this is how the href looks for the links in question: http://domain.com/lp/clkg/https/domain.com/cart.aspx?EventID=125160?gclid=CPfO1JaOx7oCFQZyQgod5A4AFw

Answer 1

Simply replace it yourself:

$(document).ready(function() {
 var params = window.location.search.replace(/\+/g,'%20'); 
 var button = $('a').each( function(i) {
 if (this.href.indexOf('?') == -1) {
 this.href = this.href + params;
 } else if (params.length) {
 this.href = this.href + '&' + params.substr(1);
 }
 });
});

Edit: and are you aware that you are replacing subsequent spaces with only one single '%20'?

• Josh Kellett: Hm, I tried using your fix above and the GClid stopped getting passed at all, so the destination URL only contains the cart parameter.
• Peter van der Wal: I had one typo ('&' . params.substr(1) should be '&' + params.substr(1) of course), for the rest it should work: jsfiddle.net/TJ5p5
• Josh Kellett: Yeah, that was it. Can confirm the above snippet works like a charm!
• Peter van der Wal: That's the problem of programming in both PHP (where string concatenation is done with a dot) and in JavaScript (where string concatenation is done with a plus-sign). This wasn't the first time I made that fault ;)
• Josh Kellett: Hey Peter, just to follow up, what's the issue with the spaces? This is code I got from Unbounce so I'm not sure what the issue is (if there is one).