function over(obj){
	var a =obj.src
		var b = a.split('/').pop().split('_');  
		
		if(b[0]=='a')
			return;
		
		if(b[0]=='n')
			b[0]='o';
		else
			b[0]='n';
				
		var c = b.join('_');
		obj.src ='../nav_img/'+ c;
}

function bf(w,h,ci,l,t){                              
	var p='width='+w+',height='+h;
	var c =ci+'.htm?'
   fenster=window.open(c,'bildfenster',p); 
   fenster.moveTo(l,t);
   fenster.focus(); 
}