/**
 * layers.js
 *
 * javascript div management functions
 */

function showLayer(layer_id, absolute) {
	if (absolute == undefined) {
		absolute = false;
	}
	var layer = document.getElementById(layer_id);
	layer.style.display = 'block';
	if (absolute == true) {
		layer.style.position = 'absolute';
	}
}

function hideLayer(layer_id, absolute) {
	if (absolute == undefined) {
		absolute = false;
	}
	var layer = document.getElementById(layer_id);
	layer.style.display = 'none';
	if (absolute == true) {
		layer.style.position = 'absolute';
	}
}

function showHideLayer(layer_id, absolute) {
	if (absolute == undefined) {
		absolute = false;
	}
	var layer = document.getElementById(layer_id);
	if (layer.style.display == 'none') {
		layer.style.display = 'block';
	} else if (layer.style.display == 'block') {
		layer.style.display = 'none';
	}
	if (absolute == true) {
		layer.style.position = 'absolute';
	}
}

function viewLayer(layer_id, visible) {
	var layer = document.getElementById(layer_id);
	
	if (visible) {
		layer.style.visibility = "visible";
	} else {
		layer.style.visibility = "hidden";
	}
}

function centerLayer(layer_id) {
	var layer = document.getElementById(layer_id);
	
	// centering of layer
	layer.style.position = "absolute";
	
	//Opera doesn't accept top percent positions
	layer.style.top = (document.body.clientHeight /2) + "px";
	layer.style.left = "50%";
	layer.style.marginLeft = "-" + (layer.offsetWidth / 2) + "px";
	layer.style.marginTop = "-" + (layer.offsetHeight/ 2) + "px";
}