/* fit the window size to match the content wrapper */
function fitWindow2Content( contentWrapper ) {
  
    // calculate necessary change in window's width
    var width = window.innerWidth - contentWrapper.clientWidth;

    // calculate necessary change in window's height
    var height = window.innerHeight- contentWrapper.clientHeight;
  
      // resize window to fit content
    window.resizeBy( -width , -height );

}