title: Javascript: window.open in a new tab but without switching
body: <p>I'm using Firefox 51.0.1 and I have the "When I open a link in a new tab, switch to it immediately" option disabled.</p>
  
  <p>But when I make a window.open(url, '_blank'), it does open in a new tab correctly, but it also switch to it immediately. I would like to avoid the last part.</p>
  
  <p>It seems like the Firefox option above is for links clicked from the browser but not for links opened from a JS event.</p>
  
  <p>Is there a way I can do that, an advance option?</p>