Delay javascript code execution inside for loop

Question

I have the following for loop:

for (var i = tileLog.length - 1; i >= 0; i--) {
    $('.' + tileLog[i]).mouseenter();
};

1 < tileLog.legth < 1025

Is there a way to delay each iteration of the loop so that mouseenter() is triggered every x miliseconds?

I have tried:

function doSetTimeout(i) {
    setTimeout(function() { $('.' + i).mouseenter(); }, 250);
}

for (var i = tileLog.length - 1; i >= 0; i--)
  doSetTimeout(tileLog[i]);

This doesn't seem to work, it just delays by 250ms then iterates through the loop

Answer 1

As an alternative to using setTimeout() you could also use setInterval().

Define a running variable in the outer scope (like your running i in the loop). In each iteration, besides calling your function, decrement the running variable. If it is below zero, stop the setInterval()`` :

var index = tileLog.length - 1,
timer = setInterval( function(){

  $('.' + tileLog[index]).mouseenter();

  index -= 1;
  if ( index < 0 ) {
    clearInterval( timer );
  }
}, 250 );

There is no actual sleep() function or something similar. Would also be problematic as JavaScript (for most cases) is single threaded and such a method would block the render thread, thus rendering your browser inaccessible.

Answer 2

There is no sleep or such in JavaScript. So your approach with timeout is correct.

var tileLog;
var i = titleLog.length - 1;

function func1() {
   $('.' + tileLog[i]).mouseenter();
   if (--i) {
     window.setTimeout(func1, 250);
   }
}

// and of course start the process
func1();