window.onload = function() {
			document.getElementById('kundenbox').style.display = 'none';
			document.getElementById('kundenlogin').onclick = function() {
				if(document.getElementById('kundenbox').style.display == 'none') {
					document.getElementById('kundenbox').style.display = 'block';
				}
				else {
					document.getElementById('kundenbox').style.display = 'none';
				}
				return false;
			}
		}