js timers

Question 1

What is a “callback” function?

Answer 1

a function passed into another function as an argument

then invoked inside the outer function to complete some kind of routine or action

Question 2

Besides adding an event listener callback function to an element or the document, what is one way to delay the execution of a JavaScript function until some point in the future?

Answer 2

set timeout method

fetch() method; starts the process of fetching a resource from the network, returning a promise which is fulfilled once the response is available

Question 3

what type of func is the setTimeout() method?

Answer 3

a global function, so you can call it directly by name without any object

Question 4

What is the default time delay if you omit the delay parameter from setTimeout() or setInterval()?

Answer 4

a value of 0 is used, meaning execute “immediately”, or more accurately, the next event cycle

browsers will enforce a minimum timeout of 4 milliseconds once a nested call to setTimeout has been scheduled 5 times

Question 5

What do setTimeout() and setInterval() return?

Answer 5

The returned timeoutID/intervalID is a positive integer value which identifies the timer/interval created by the call

Question 6

How can you set up a function to be called repeatedly without using a loop?

Answer 6

To call a function repeatedly (e.g., every N milliseconds), consider using setInterval()

Question 7

how to cancel setTimeout?

Answer 7

clearTimeout() to cancel the timeout