// Functions by Matthyz webdesign & development - www.matthyz.nl; copying is not allowed
function showIMG(imgID) {
	document.getElementById("JSimg").style.height = '100%';	
	document.getElementById("JSimg").style.top = getcenter(500)+'px';
	document.getElementById("JSimg").innerHTML = '<center><img src="images/'+imgID+'.jpg" class="photo" onclick="hideIMG()"></center>';	
	
	var Cstyle = document.getElementById("content").style;	
	Cstyle.opacity = 0.4;
	Cstyle.MozOpacity = 0.4;
	Cstyle.KhtmlOpacity = 0.4;
	Cstyle.filter = "alpha(opacity=" + 40 + ")";
}
function hideIMG() {
	var Cstyle = document.getElementById("content").style;
	Cstyle.opacity = 1;	
	Cstyle.MozOpacity = 1;
	Cstyle.KhtmlOpacity = 1;
	Cstyle.filter = "alpha(opacity=" + 100 + ")";
	document.getElementById("JSimg").innerHTML = '';	
	document.getElementById("JSimg").style.top = '0px';
	document.getElementById("JSimg").style.height = '0px';
}
function getcenter(height) {
	var Ya = parseFloat(window.pageYOffset);	
	var Yb = parseFloat(document.body.scrollTop);	
	var Yc = parseFloat(document.documentElement.scrollTop);	
	if(!isNaN(Ya)&&Ya!=0) {Y=Ya;} else if(!isNaN(Yb)&&Yb!=0) {Y=Yb;} else if(!isNaN(Yc)&&Yc!=0) {Y=Yc;} else {Y=0;}
	
	var Sa = parseFloat(window.innerHeight);	
	var Sb = parseFloat(document.body.clientHeight);	
	var Sc = parseFloat(document.documentElement.clientHeight);	 
	if(!isNaN(Sa)&&Sa!=0) {S=Sa;} else if(!isNaN(Sb)&&Sb!=0) {S=Sb;} else if(!isNaN(Sc)&&Sc!=0) {S=Sc;} else {S=0;}	
	
	var top = (0.5*(S-height))+Y; return top;
}