/**
 * addEvent written by Dean Edwards, 2005
 * with input from Tino Zijdel
 *
 * http://dean.edwards.name/weblog/2005/10/add-event/
 **/
function addEvent(element, type, handler) {
	// assign each event handler a unique ID
	if (!handler.$$guid) handler.$$guid = addEvent.guid++;
	// create a hash table of event types for the element
	if (!element.events) element.events = {};
	// create a hash table of event handlers for each element/event pair
	var handlers = element.events[type];
	if (!handlers) {
		handlers = element.events[type] = {};
		// store the existing event handler (if there is one)
		if (element["on" + type]) {
			handlers[0] = element["on" + type];
		}
	}
	// store the event handler in the hash table
	handlers[handler.$$guid] = handler;
	// assign a global event handler to do all the work
	element["on" + type] = handleEvent;
};
// a counter used to create unique IDs
addEvent.guid = 1;

function removeEvent(element, type, handler) {
	// delete the event handler from the hash table
	if (element.events && element.events[type]) {
		delete element.events[type][handler.$$guid];
	}
};

function handleEvent(event) {
	var returnValue = true;
	// grab the event object (IE uses a global event object)
	event = event || fixEvent(window.event);
	// get a reference to the hash table of event handlers
	var handlers = this.events[event.type];
	// execute each event handler
	for (var i in handlers) {
		this.$$handleEvent = handlers[i];
		if (this.$$handleEvent(event) === false) {
			returnValue = false;
		}
	}
	return returnValue;
};

function fixEvent(event) {
	// add W3C standard event methods
	event.preventDefault = fixEvent.preventDefault;
	event.stopPropagation = fixEvent.stopPropagation;
	return event;
};
fixEvent.preventDefault = function() {
	this.returnValue = false;
};
fixEvent.stopPropagation = function() {
	this.cancelBubble = true;
};

// end from Dean Edwards


/**
 * Creates an Element for insertion into the DOM tree.
 * From http://simon.incutio.com/archive/2003/06/15/javascriptWithXML
 *
 * @param element the element type to be created.
 *				e.g. ul (no angle brackets)
 **/
function createElement(element) {
	if (typeof document.createElementNS != 'undefined') {
		return document.createElementNS('http://www.w3.org/1999/xhtml', element);
	}
	if (typeof document.createElement != 'undefined') {
		return document.createElement(element);
	}
	return false;
}

/**
 * "targ" is the element which caused this function to be called
 * from http://www.quirksmode.org/js/events_properties.html
 **/
function getEventTarget(e) {
	var targ;
	if (!e) {
		e = window.event;
	}
	if (e.target) {
		targ = e.target;
	} else if (e.srcElement) {
		targ = e.srcElement;
	}
	if (targ.nodeType == 3) { // defeat Safari bug
		targ = targ.parentNode;
	}

	return targ;
}

/**
 * The following code is for the caffeine database and allows change from US to metric amounts
 **/
 
 var curUnit="oz";
var OUNCE = 29.5735297;

function chgUnits (caller) {
	var convType = 0;
	var cafTbl = document.getElementById('caffeinedb');
	var row = cafTbl.tHead.rows[0];
	var items = cafTbl.rows;
	var rounder = 10;
	
	if (curUnit == "oz" && caller.value == 2) {
		convType = 2;
	} else {
		if (curUnit == "ml" && caller.value == 1) {
			convType = 1;
		}
	}

	switch (convType){
		case 1:
		  //Change Column headers
			row.cells[1].childNodes[0].innerHTML="Ounces";
			row.cells[3].childNodes[0].innerHTML="mg/oz";
	
			// Mls to Ounces
			var elsLen = items.length;
			for (var i = 1; i < elsLen; i++) {
				amt = items[i].cells[1];
				newAmt = amt.innerHTML / OUNCE;
				rounder = 10;
				if (amt.innerHTML == "350") {
					rounder = 100;
				} //exception for non-US beverages
				
				amt.innerHTML = Math.round(newAmt*rounder)/rounder; 
				items[i].cells[3].innerHTML = Math.round((items[i].cells[2].innerHTML / amt.innerHTML)*100)/100;
				
			}
			
			curUnit = "oz";
		break;
		
		case 2:
			//Change Column headers
			row.cells[1].childNodes[0].innerHTML="mls";
			row.cells[3].childNodes[0].innerHTML="mg/100mls";

			//Ounces to mls
			var elsLen = items.length;
			for (var i = 1; i < elsLen; i++) {
			  amt = items[i].cells[1];
				amt.innerHTML = Math.round(amt.innerHTML * OUNCE);
				items[i].cells[3].innerHTML = Math.round(100*(items[i].cells[2].innerHTML / amt.innerHTML));
			}
			curUnit = "ml" ;
		break;
	}
}