How to capture if a visitor is from a google adwords click

Question

When a user signs up on my site I want to be able to store whether or not they came to my site via an Adwords campaign.

I know google uses javascript to track conversio

Answer 1

I know this already has an accepted answer but it's very out of date. The updated way can be found here: https://support.google.com/analytics/answer/1033981?hl=en

C+P'd:

In order for Analytics to display details about your AdWords keywords and costs, you must do one of the following:

Enable auto-tagging. This is the recommended approach and ensures that you get the most detailed AdWords data. Manually tag all your keyword final URLs with tracking variables. You should only do this in the special cases outlined below.

How auto-tagging works Auto-tagging automatically imports AdWords data into Analytics. Combining AdWords data with the rich post-click information provided by Analytics allows you to see what happened on your site after people clicked on your ads.

When you enable auto-tagging, a parameter called gclid is added to your landing page URL when a user clicks over to your site from an ad. For example, if your site is www.mysite.com, when a user clicks on your ad it appears in the address bar as:

www.mysite.com/?gclid=123xyz

Enable auto-tagging To enable/disable auto-tagging:

Sign in to your AdWords account. Click the gear icon, and select Account settings. Make sure you're on the Preferences tab, and click Edit in the Tracking section. Select (enable) or clear (disable) the Auto-tagging checkbox. Click Save changes.