Open window in new tab, avoiding popup blocker

open.js

var link = document.getElementById('link');

function open() {
  var w = window.open('', 'MyWindow');
  
  // Ajax call
  setTimeout(function() {
    w.location.href = 'http://example.com';
  }, 100);
}

link.addEventListener('click', open);

This doesn't work because the location.href is set inside a callback function for setTimeout(). Even though the timer is triggered by the user, it shouldn't work. The browser sees this as an automated timer triggering the redirection. The location.href must be inside a user-driven event callback for a "popup" to be allowed.