NS4 = (document.layers) ? 1 : 0;
IE4 = (document.all) ? 1 : 0;
NS6 = (document.getElementById) ? 1 : 0;
ver4 = (NS4 || IE4) ? 1 : 0;

function showPopUp() {
	document.getElementById('project_curtain').style.display = "block";
	document.getElementById('popup').style.display = "block";
}

function closePopUp() {
	document.getElementById('project_curtain').style.display = "none";
	document.getElementById('popup').style.display = "none";
}

function showHide(layername, hide_others) {
	if (hide_others != null) {
		for (i=1;i<=14;i++) {
			Hide('sub_' +i);
		}
	}
	if (NS4) {
		if (document.layers[layername].display == "none")
			document.layers[layername].display = "block";
		else {
			document.layers[layername].display = "none";
		}
	}
	else if (NS6) {
		if (document.getElementById(layername).style.display == "none")
			document.getElementById(layername).style.display = "block";
		else {
			document.getElementById(layername).style.display = "none";
		}
	}
	else {
		if (document.all[layername].style.display == "none")
			document.all[layername].style.display = "block";
		else {
			document.all[layername].style.display = "none";
		}
	}
}

function Show(layername) {
	if (NS4) {
		if (document.layers[layername].display == "none") {
			document.layers[layername].display = "block";
		}
	}
	else if (NS6) {
		if (document.getElementById(layername).style.display == "none") {
			document.getElementById(layername).style.display = "block";
		}
	}
	else {
		if (document.all[layername].style.display == "none") {
			document.all[layername].style.display = "block";
		}
	}
}

function Hide(layername) {
	if (NS4) {
		if (document.layers[layername].display == "block")
			document.layers[layername].display = "none";
	}
	else if (NS6) {
		if (document.getElementById(layername).style.display == "block")
			document.getElementById(layername).style.display = "none";
	}
	else {
		if (document.all[layername].style.display == "block")
			document.all[layername].style.display = "none";
	}
}

function SwitchImg( filename, height ) {
	
	document.replace.src='/img/projects/' + filename;
	document.getElementById('project_big').style.height=height + 'px';
	
}

function SwitchGuideImg( filename ) {
	
	document.replace.src='/img/' + filename;
	
}

function SwitchGuideFooterIgm( nr ) {
	
	var second 	= nr + 1;
	var third 	= nr + 2;
	
	document.f_0.src='/img/rondleiding_small_' + nr + '.jpg';
	document.f_1.src='/img/rondleiding_small_' + second + '.jpg';
	document.f_2.src='/img/rondleiding_small_' + third + '.jpg';
	
}