What does setTimeout return?
javascript
Solution
It's a handle (a unique identifier). When you create a timeout, the JavaScript runtime associates a handle with the timeout you created, and it can identify that timeout by the handle `setTimeout()` returns. When you run `clearTimeout()`, it will know what timeout you're talking about by looking at the unique handle you pass in.
Problem
I was curious that what does setTimeout return. So I did a quick test: ``` var thing = setTimeout(function(){},1); ``` And what surprise me is that it gave me a number. `1351` Each time is different. So is it really all it returns is a number? So I can actually do this as well? ``` clearTimeout(1351); ``` Very confusing...