Javascript - Thread Wait ?

Web API setTimeout

The setTimeOut is wrapper around code that create a job to execute it later. The execution of the thread (of the code) does not stop.

See Browser - setTimeOut

Promise

function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

async function demo() {
  console.log('Taking a break...');
  await sleep(2000);
  console.log('Two second later');
}

var button = document.getElementById("startButton");
button.addEventListener("click", function () { demo() }, false);

<button id="startButton">Start Demo</button>

JQuery

$('#warning')
.addClass('highlight')
.delay(1000)
.removeClass('highlight');