Comment centrer une fenêtre contextuelle sur l'écran de l'utilisateur à l'aide de JavaScript ?

<code class="javascript">const popupCenter = ({url, title, w, h}) => {
    // Handle dual-screen position
    const dualScreenLeft = window.screenLeft !== undefined ? window.screenLeft : window.screenX;
    const dualScreenTop = window.screenTop !== undefined ? window.screenTop : window.screenY;

    // Get browser window dimensions
    const width = window.innerWidth || document.documentElement.clientWidth || screen.width;
    const height = window.innerHeight || document.documentElement.clientHeight || screen.height;

    // Account for system zoom to obtain accurate dimensions
    const systemZoom = width / window.screen.availWidth;
    const left = (width - w) / 2 / systemZoom + dualScreenLeft
    const top = (height - h) / 2 / systemZoom + dualScreenTop
    const newWindow = window.open(url, title, 
      `
      scrollbars=yes,
      width=${w / systemZoom}, 
      height=${h / systemZoom}, 
      top=${top}, 
      left=${left}
      `
    )

    if (window.focus) newWindow.focus();
}</code>

<code class="javascript">popupCenter({url: 'http://www.example.com', title: 'Popup Window', w: 500, h: 300}); </code>