function screenSize() {
      var w, h; 
      w = (window.innerWidth ? window.innerWidth : (document.documentElement.clientWidth ? document.documentElement.clientWidth : document.body.offsetWidth));
      h = (window.innerHeight ? window.innerHeight : (document.documentElement.clientHeight ? document.documentElement.clientHeight : document.body.offsetHeight));
      return {w:w, h:h};
  }

  function screenSizeStart() {
      //alert(screenSize().h);
      var obj = document.getElementById("container1");
      obj.style.height = screenSize().h - 169 - 75; //height=169px - a start header and height=75px - a start footer
  }

  function screenSizeDefault() {
      //alert(screenSize().h);
      var obj = document.getElementById("container1");
      obj.style.height = screenSize().h - 75; //height=75px - a default footer
  }