window.onload = initialize;

function initialize() {
	tabNum = 0;
	document.getElementById("tab"+tabNum).style.fontWeight = "bold";	
	document.getElementById("tab"+tabNum+"_content").style.display = "block";
	
	tabLength = 0;
	n = document.getElementById("tabs").childNodes;
	for (i=0; i<n.length; i++) {
		if (n.item(i).id && n.item(i).id.indexOf('tab') >= 0) {
			n.item(i).onclick = new Function("changeTab(" + tabLength + ")");
			tabLength ++;
		}
	}
}

function changeTab(n) {
	if ( n != tabNum && document.getElementById("tab"+n+"_content") ) {
		document.getElementById("tab"+tabNum).style.fontWeight = "normal";
		document.getElementById("tab"+tabNum+"_content").style.display = "none";
		document.getElementById("tab"+n).style.fontWeight = "bold";
		document.getElementById("tab"+n+"_content").style.display = "block";
		tabNum = n;
	}
}


function move_focus(n) {
	var focus_new = n + tabNum;
	if ( focus_new > tabLength )
		return false;
	
	var e = document.getElementById("tab"+ focus_new);
	if(e) e.onclick();
	
}