// cf. www.thestandardhack.com/components/labels.html (soon my friend)
addEvent(window, "load", labels_init);

// Setup
// - turn display of labels off
// - initialize all labels
// - arrange for uninit to be called before any form submissions
function labels_init() {
	if (document.getElementById && document.getElementsByTagName) {
		try {
			var nalist = new Array(1)
				nalist[0] = "app-login";
			
			var j = 0;
			while (j < nalist.length) {
				if(document.getElementById(nalist[j])) {
					var allElements = document.getElementById(nalist[j]).getElementsByTagName("label");
					var i = 0;
					while (i < allElements.length) {
						allElements[i].parentNode.className += " wjs";
						label_init(allElements[i]);
						i++;
					}
				}
				var allElements = document.getElementById(nalist[j]).getElementsByTagName("form");
				var i = 0;
				while (i < allElements.length) {
					addEvent(allElements[i], "submit", labels_uninit);
					i++;
				}
				j++;
			}
		} 
		catch (e) { }
	}
}

// tear-down.
// - clear all labels so they don't accidentally get submitted to the server
function labels_uninit(e) {
	if (document.getElementById && document.getElementsByTagName) {
		for (var i = 0, label = null; 
			(label = document.getElementsByTagName("label")[i]); 
			i++) 
		{
			var el = document.getElementById(label.htmlFor);
			if (el && el.value == el._labeltext) label_hide(el);
		}
	}
}

// initialize a single label.
// - only applicable to textarea and input[text] and input[password]
// - arrange for label_focused and label_blurred to be called for focus and blur
// - show the initial label
// - for other element types, show the default label
function label_init(label) {
	try {
		var el = document.getElementById(label.htmlFor);
		var elName = el.nodeName;
		var elType = el.getAttribute("type");

		if (elName == "TEXTAREA" 
		|| (elType == "text" || elType == "password")) {
			el._labeltext = label.firstChild.nodeValue;
			el._type = el.getAttribute("type");
			addEvent(el, "focus", label_focused);
			addEvent(el, "blur", label_blurred);
			label_blurred({currentTarget:el});
		} else {
			label.style.position = "static";
			label.style.visibility = "visible";
		}
	}
	catch (e) { 
		label.style.position = "static";
		label.style.visibility = "visible";
	}
}

function label_focused(e) {
	e = fix_e(e);
	var el = e.currentTarget;
	if (el.value == el._labeltext) el = label_hide(el);
	el.focus();
	// without this extra focus() the script doesn't focus on PASSWORD fields in MSIE
	el.focus();
}

function label_hide(el) {
	if (el._type == "password") el = label_setInputType(el, "password");
	el.value = "";
	return el;
}

function label_blurred(e) {
	e = fix_e(e);
	var el = e.currentTarget;
	if (el.value == "") el = label_show(el);
}

function label_show(el) {
	if (el._type == "password") el = label_setInputType(el, "text");
	el.value = el._labeltext;
	return el;
}

// XXX hack:
// msie won't let us change the type of an existing input element, so to get this 
// functionality, we need to create the desired element type in an HTML string.
function label_setInputType(el, type) {
	if (navigator.appName == "Microsoft Internet Explorer") {
		var newEl = document.createElement("SPAN");
		newEl.innerHTML = "<input type='" + type + "' />";
		newEl = newEl.firstChild;
		var s = "";
		for (prop in el) {
			// some properties are read-only
			try {
				// the craziest browser bug ever: "height" and "width" (which 
				// should not even exist) return totally garbage numbers, like 
				// 458231 for instance, so we need to ignore those.
				if (prop != "type"
				&& prop != "height"
				&& prop != "width") newEl[prop] = el[prop];
			} 
			catch(e) { }
		}
		addEvent(newEl, "focus", label_focused);
		addEvent(newEl, "blur", label_blurred);
		el.parentNode.replaceChild(newEl, el);
		return newEl;
	} else {
		el.setAttribute("type", type);
		return el;
	}
}


// makes ie behave like a sc browser with regard to events
function fix_e(e) {
	if (!e && window.event) e = window.event;
	if (!e.currentTarget && e.srcElement) e.currentTarget = e.srcElement;
	if (!e.originalTarget && e.srcElement) e.originalTarget = e.srcElement;
	// paul:
	// we can put more things in here as we go along, 
	// whenever we come across differences that need to
	// be fixed.
	return e;
}