function agentName() {
	if (navigator.appName.indexOf("Microsoft") != -1) {
		return "IE";
	} else {
		if (navigator.appVersion.indexOf("Safari") != -1) {
			return "Safari";
		} else {
			return "Mozilla";
		}
	}
}

function divHeight(divName) {
	//Uitlezen hoogte div. Dit werkt in IE, Mozilla en Safari.
	docObj = document.getElementById(divName);
	//docObj.style.height = "auto";
	return parseInt(docObj.offsetHeight);
}

function leftHeight() {
	return divHeight('left-top')+divHeight('left-middle')+divHeight('left-bottom');
}

function middleHeightHome() {
	return divHeight('middle-top')+divHeight('middle-bottom');
}

function middleHeightSub() {
	return divHeight('middle-top');
}

function rightHeight() {
	return divHeight('right-top');
}

function stretchHome() {
//Opvullen kolommen op home pagina

	//Vaststellen hoogte linker, middelste en rechter kolom.
	left=leftHeight();
	middle=middleHeightHome();
	right=rightHeight();
	marginF=0;
	
	if (left > middle && left > right) {
		//Linker kolom is het grootst
		if (agentName() == "IE") {
			marginM=24;
			marginR=marginM-2;
			marginF=10;
		} else if (agentName() == "Safari") {
			marginM=24;
			marginR=marginM-2;
		} else {
			marginM=34;
			marginR=marginM-13;
		}
		
		stretchM=left-divHeight('middle-top')-marginM;
		stretchR=left-marginR;
		stretchDiv="homeL";
		
		document.getElementById("middle-stretch").style.height=stretchM+'px';
		document.getElementById("right-stretch").style.height=stretchR+'px';
		
	} else if (middle > left && middle > right) {
		//Middelste kolom is het grootst
		if (agentName() == "IE") {
			marginL=28;
			marginR=marginL-4;
			marginF=10;
		} else if (agentName() == "Safari") {
			marginL=28;
			marginR=marginL-4;
		} else {
			marginL=39;
			marginR=marginL-15;
		}
		
		stretchL=middle-divHeight('left-top')-divHeight('left-middle')-marginL;
		stretchR=middle-marginR;
		stretchDiv="homeM";
		
		document.getElementById("left-stretch").style.height=stretchL+'px';
		document.getElementById("right-stretch").style.height=stretchR+'px';
	
	} else {
		//Rechter kolom is het grootst
		if (agentName() == "IE") {
			marginL=30;
			marginM=marginL-2;
			marginF=10;
		} else if (agentName() == "Safari") {
			marginL=30;
			marginM=marginL-2;
		} else {
			marginL=41;
			marginM=marginL-2;
		}
		
		stretchL=right-divHeight('left-top')-divHeight('left-middle')-marginL;
		stretchM=right-divHeight('middle-top')-marginM;
		stretchDiv="homeR";
		
		document.getElementById("left-stretch").style.height=stretchL+'px';
		document.getElementById("middle-stretch").style.height=stretchM+'px';
	}
	
	setFooter(stretchDiv);

}

function stretchSub() {
//Opvullen kolommen op vervolgpagina's
	
	//Vaststellen hoogte linker en middelste kolom
	left=leftHeight();
	middle=middleHeightSub();
	marginF=0;
	
	if (left > middle) {
		//Linker kolom is het grootst
		if (agentName() == "IE") {
			marginM=22;
			marginF=10;
		} else if (agentName() == "Safari") {
			marginM=22;
		} else {
			marginM=20;
		}
		
		stretchDiv="subL";
		stretchM=left-marginM;
		document.getElementById("middle-stretch").style.height=stretchM+'px';
		
	} else {
		//Middelste kolom is het grootst
		marginL=30;
		if (agentName() == "IE") {
			marginF=10;
		}
		
		stretchDiv="subM";
		stretchL=middle-divHeight('left-top')-divHeight('left-middle')-marginL;
		document.getElementById("left-stretch").style.height=stretchL+'px';
	}
	
	setFooter(stretchDiv);
}

function setFooter(divName) {
	//Footer onder de drie hoofdkolommen (homeL, homeM en homeR) plaatsen 
	document.getElementById("footer").style.top=divHeight("topnav")+divHeight("head")+divHeight(divName)+marginF+'px';
}