What number does 8e3 evaluate to?

Question

I encountered this code today:

b = setTimeout(function () {
    // do some javascript stuff here
}, 8e3)

The timeout is set to 8e3

Answer 1

This is called floating point notation or scientific notation. It is 8×10³, which is 8000 miliseconds. The e stands for 10th exponent. Let me give you some more examples:

1e3    = 1000        // 1×10³
1e0    = 1           // 1×10⁰
1e-1   = 0.1         // 1×10⁻¹ -> Works also for the negatives
1.23e9 = 1230000000  // And really makes sense to shorten big numbers

There is also an wikipedia article on that topic: Scientific Notation