Detecting Client information Javascript/Jquery

Question

I want to be able to get information about users that open my emails. After mailchimp does it I thought it would be a really good way to get into javascript better. (No, I am not trying to take on Mailchimp)

After some research I found that mailchimp put a 1x1 image in the email which is loaded from their server. for example:

<img src="http://mailchimp.com/?userid=23456" />

My questions are: How, using Javascript/Jquery do they then detect the email client/ or whether it's webmail? Is it possible with this language or should another language be used?

I'm struggling because I know you can detect browser information but a browser is not actually opened for this.

If you can't tell I am a little nooby, please help me in the right direction.

Answer 1

"User-Agent" based detection is not a reliable solution in most cases, because:

• The rules (regular expressions) are constantly out-dated and incomplete
• You have to update the detection code continuously

However, this is one of the best libraries I have found so far:

http://hgoebl.github.io/mobile-detect.js/