If you want to hack Gmail UI, to build web extension or any other similar tool that works on top of Gmail, you always want or need to trigger some DOM events in Gmail UI, like you want to click on some buttons/icons, to send out email, to make the compose window pop out, etc.

You can’t do it by simply use click function, either by Vanilla JS or jQuery, either click or trigger function can not achieve your goal.

You need to do this by using Document.createEvent().

Take click for example, you want to click an icon:

  const mouseDown = document.createEvent('MouseEvents');
  mouseDown.initEvent('mousedown', true, false);

  const mouseUp = document.createEvent('MouseEvents');
  mouseUp.initEvent('mouseup', true, false);

You may want to make it as a function so that you can use it click any element.