document.getElementsByClassName = function(cl) {
	var retnode = [];
	var myclass = new RegExp('\\b'+cl+'\\b');
	var elem = this.getElementsByTagName('*');
	for (var i = 0; i < elem.length; i++) {
	  var classes = elem[i].className;
	  if (myclass.test(classes)) retnode.push(elem[i]);
	}
	return retnode;
};

function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		rhinobook_overview_o = newImage("images/rhinobook_overview_o.jpg");
		rhinobook_overview_c = newImage("images/rhinobook_overview_c.jpg");
		rhinobook_specs_c = newImage("images/rhinobook_specs_c.jpg");
		rhinobook_specs_o = newImage("images/rhinobook_specs_o.jpg");
		rhinobook_why_c = newImage("images/rhinobook_why_c.jpg");
		rhinobook_why_o = newImage("images/rhinobook_why_o.jpg");
		rhinobook_tests_c = newImage("images/rhinobook_tests_c.jpg");
		rhinobook_tests_o = newImage("images/rhinobook_tests_o.jpg");
		rhinobook_images_c = newImage("images/rhinobook_images_c.jpg");
		rhinobook_images_o = newImage("images/rhinobook_images_o.jpg");
		rhinobook_downloads_c = newImage("images/rhinobook_downloads_c.jpg");
		rhinobook_downloads_o = newImage("images/rhinobook_downloads_o.jpg");
		rhinobook_buy_c = newImage("images/rhinobook_buy_c.jpg");
		rhinobook_buy_o = newImage("images/rhinobook_buy_o.jpg");
		preloadFlag = true;
	}
}

function highlightTab(obj) {
	obj.src = "images/rhinobook_" + obj.name.substr(0,obj.name.indexOf('_')) + "_o.jpg";
}

function restoreTab(obj) {
	obj.src = "images/rhinobook_" + obj.name.substr(0,obj.name.indexOf('_')) + ".jpg";
}


function selectTabByName(tabname){
	var opentabs = document.getElementsByClassName("open_tab");
	for (var i = 0; i < opentabs.length; i++) {
	  opentabs[i].style.display = 'none';
	}
	document.getElementById(tabname + "_tab").style.display = 'block';

	var tabcontents = document.getElementsByClassName("tab_content");
	for (var i = 0; i < tabcontents.length; i++) {
	  tabcontents[i].style.display = 'none';
	}
	document.getElementById(tabname + "_content").style.display = 'block';
    dhtmlHistory.add(tabname);
}

function selectTab(obj) {
	selectTabByName(obj.name)
}