Functions that simulate sync sleep

sleep.js

function sleep(milliseconds) {
  var start = new Date().getTime();
  for (var i = 0; i < 1e7; i++) {
    if ((new Date().getTime() - start) > milliseconds){
      break;
    }
  }
}

sleep2.js

for (let i=1; i<10; i++) {
    setTimeout(function timer(){
        console.log(i);
    }, i*3000 );
}

sleep3.js

var i = 0, howManyTimes = 10;
function f() {
    alert( "hi" );
    i++;
    if( i < howManyTimes ){
        setTimeout( f, 3000 );
    }
}
f();