function getHeight() {
  var _height = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    _height = window.innerHeight;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    _height = document.documentElement.clientHeight;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    _height = document.body.clientHeight;
  }
  return _height - 50;
}

function getWidth() {
  var _width = 0;
  if( typeof( window.innerWidth ) == 'number' ) {
    //Non-IE
    _width = window.innerWidth;
  } else if( document.documentElement && ( document.documentElement.clientWidth || document.documentElement.clientHeight ) ) {
    //IE 6+ in 'standards compliant mode'
    _width = document.documentElement.clientWidth;
  } else if( document.body && ( document.body.clientWidth || document.body.clientHeight ) ) {
    //IE 4 compatible
    _width = document.body.clientWidth;
  }
  return _width;
}