function changeTab(index){
	var tabElements = getElementsByClass("tab");
	//unselect currently selected tab
	for(i=0; i < tabElements.length;i++){
		tabElements[i].style.backgroundColor = "#396B9C";
		tabElements[i].style.color = "#FFFFF0";
	}

	//select tab with given index
	tabElements[index-1].style.backgroundColor = "#FFFFF0";
	tabElements[index-1].style.color = "#396B9C";

	var infoElements = getElementsByClass("tabinfoarea");
	//unselect currently selected tabinfoarea
	for(j=0; j<infoElements.length;j++){
		infoElements[j].style.display = "none";
		infoElements[j].style.visibility = "hidden";
	}

	//select tabinfoarea with given index, MUST USE DISPLAY INLINE TO FIX IE MARGIN BUG
	infoElements[index-1].style.display = "inline";
	infoElements[index-1].style.visibility="visible";

}

var last_tab = 'tab1'; // default value
function show(tabName) {
  document.getElementById(tabName).style.display = 'inline';
  document.getElementById(tabName).style.visibility = 'visible';
}

function hide(tabName) {
  document.getElementById(tabName).style.display = 'none';
  document.getElementById(tabName).style.visibility = 'hidden';
}

function show_tab(obj,tab_class) {
  // tab_name = obj.id;
  cur_tab = obj;
  document.getElementById(last_tab).className = tab_class; // 'infoTab'; set last tab to normal info tab class
  document.getElementById(cur_tab).className = tab_class+'Active';
  // var curr = document.getElementById(tab_name); // get curent tab name by ID
  // curr.className = tab_class+'Active'; //'infoTabActive'; set currrent tab class to active
  hide(last_tab+'_content');  // hide last tab
  show(cur_tab+'_content');  // set current tab visible
  last_tab = cur_tab;
}