How can I generate a string of numbers and letters in Javascript?

pretty simple question that has been eluding me lately.

What I want to do is generate a line of numbers and letters in this format using Javascript.

Example:F35-HE4E-WAD-32S

So a line of 3-4-3-3 of random numbers and letters. If you could point me in the right direction I would really appreciate it. Thank you!