var opa=0;
document.p = null;
var plaatje=2;
for(var tel=3;tel<=8;tel++) //preload
	document.createElement("IMG").src='_resources/img_struct/'+tel+'.gif';
	
if(document.p) window.clearTimeout(document.p);	

window.onload=function(){window.setTimeout("lucht()", 140);};
		
function lucht() {

	if(document.p) window.clearTimeout(document.p);
	
	opa+=0.01;
	
	if(opa>=1.5) {
	
		opa=0;
		document.getElementById('lucht1').src='_resources/img_struct/'+plaatje+'.gif';
		if(++plaatje>8)	plaatje=1;
		_setOpacity(document.getElementById('lucht2'),0);
		_setOpacity(document.getElementById('lucht1'),1);
		document.getElementById('lucht2').src='_resources/img_struct/'+plaatje+'.gif';
		document.p = window.setTimeout("lucht()", 400);
	}
	else {
		_setOpacity(document.getElementById('lucht2'),(opa>1?1:opa))
		_setOpacity(document.getElementById('lucht1'),(opa>0.5?1.5-opa:1))
		document.p = window.setTimeout("lucht()", 140);
	}

	function _setOpacity(obj,value) {
	
		obj.style.opacity = value;
		obj.style.MozOpacity = value;
		obj.style.filter = "alpha(opacity=" + (value*100) + ")";
	}
}