function getInnerSize(){
   var width,height;
   var minWidth  = 1000;
   var minHeight = 520;

   var maxWidth  = 1400;
   var maxHeight = 700;

	if( self.innerHeight ) // all except Explorer
	{
		width  = self.innerWidth;
		height = self.innerHeight;
	}
	else if ( document.documentElement && document.documentElement.clientHeight )
	{
	   minWidth = 975; // IE hat zusätzliche Vertical-Scrollbar
		width    = document.documentElement.clientWidth;
		height   = document.documentElement.clientHeight;
	}
	else if (document.body) // other Explorers
	{
		width  = document.body.clientWidth;
		height = document.body.clientHeight;
	}

	width  -= 20;
	height -= 50;

   // Minimal begrenzen
   width   = ( width  <  minWidth )  ? minWidth  : width;
   height  = ( height <  minHeight ) ? minHeight : height;

   // Maximal begrenzen
   width   = ( width  >  maxWidth )  ? maxWidth  : width;
   height  = ( height >  maxHeight ) ? maxHeight : height;

   return {width:width,height:height};
}