why is a comma used before "contents" [duplicate]

Question

I saw the following snippet in a jquery code, but I don't understand why it uses a comma right before 'contents' instead of a period.

var that = $(this),
contents = that.serialize();

Does anyone have an idea why a comma is being used?

I am missing the words to search properly I think.

Answer 1

same as :

var that = $(this);
var contents = that.serialize();