function visibilityCheck() { 
	if (navigator.userAgent.indexOf("Opera") != -1) {
	
	}
	else {
		if (window.innerWidth) {
			var w = window.innerWidth;
			var h = window.innerHeight;
			if(w < 1420) {
				document.getElementById('bottom_right_image').style.display='none';
			}
			else if(h < 250) {
				document.getElementById('bottom_right_image').style.display='none';
			}
			else {
				document.getElementById('bottom_right_image').style.display='block';
			}
		}
		else if (document.documentElement.offsetWidth) {
			var w = document.documentElement.offsetWidth;
			var h = document.documentElement.offsetHeight;
			
			if(w < 1400) {
				document.getElementById('bottom_right_image').style.display='none';
			}
			else if(h < 250) {
				document.getElementById('bottom_right_image').style.display='none';
			}
			else {
				document.getElementById('bottom_right_image').style.display='block';
			}
		}
	}
	
	/*alert("Die aktuelle Fenstergröße\n Breite: " +w+" Höhe: "+h+ " Pixel");*/
}