I've been asked this question many times by various clients, mostly in relation to how to track SiteCatalyst links. There are several methods to test link tracking. I've listed my two favorites below.
Event Testing in Chrome
After opening the developer tools, navigate to the page you'd like to test an event on. After the page has loaded, go to the network tab. Then, clear all sources. Thirdly, click the "preserve log" box.
Now, if you are looking for a SiteCatalyst call, you can filter in the filter box above with the text "/ss":
Now that you are setup to receive the tracking call, click the event you'd like to track (e.g. cart add). Immediately, you'll get some network calls to appear, followed by the page redirect, followed by more network calls. After the page has finished loading, you can look at the first call that appeared in the network tab. This will be the event call from the click.
You can view the params that were sent to SC by clicking on the actual request, then scrolling down to the "query string parameters" section:
Event Testing in Firefox
Event testing in Firefox is almost the same process as chrome if you install Firebug to be your debugger. However, there is a firebug tool that makes it even easier called Omnibug.
Download firebug: https://getfirebug.com/
Download omnibug for firebug: http://omnibug.rosssimpson.com/
After installing both those, you'll have a new tab in firebug. It's similar to something like observepoint, but it will track requests from previous pages (e.g. link clicks). It will also specifically point out link clicks and format them in a readable fashion when you expand them:
Obviously, there's many other tools and methods on finding the same information for SiteCatalyst (or any other tag). If you've found a favorite, feel free to share in the comments!