function getElementsByClass (needle, node, tagName) {
	var elements = node.getElementsByTagName (tagName);
	var found = Array ();

	for (var i = 0, j = 0; i < elements.length; i++) {
		var c = " " + elements[i].className + " ";
		if (c.indexOf (" " + needle + " ") != -1) {
			found[j++] = elements[i];
		}
	}
	return found;
}

var campaignTab;
var campaignImageName;

function campaignOver () {
	caid = this.id.split ('_')[1];
	if (campaignTab) {
		campaignTab.src = self['tab_' + caid].src;
	}
}

function campaignOut () {
	if (campaignTab) {
		campaignTab.src = original;
	}
}

function initCampaigns () {
	var name;
	
	for (caid in campaignImages) {
		filename = campaignImages[caid];
		self['tab_' + caid] = new Image ();
		self['tab_' + caid].src = imagePath + filename;
	}
	
	campaignTab = document.getElementById ('campaign_tab');
	original = campaignTab.src;
	
	var buttons = getElementsByClass ('campaign_button', document, 'A');
	for (var i = 0; i < buttons.length; i++) {
		buttons[i].onmouseover = campaignOver;
		buttons[i].onmouseout = campaignOut;
	}
}

window.onload = initCampaigns;