// wForms - a javascript extension to web forms.
// see http://www.formassembly.com/wForms
// This software is licensed under the CC-GNU LGPL <http://creativecommons.org/licenses/LGPL/2.1/>

function wHELPERS() {};

// addEvent adapated from http://ejohn.org/projects/flexible-javascript-events/
// and  Andy Smith's (http://weblogs.asp.net/asmith/archive/2003/10/06/30744.aspx)
wHELPERS.prototype.addEvent = function(obj, type, fn) {
	if(!obj) { return; }
	
	if (obj.attachEvent) {
		obj['e'+type+fn] = fn;
		obj[type+fn] = function(){obj['e'+type+fn]( window.event );}
		obj.attachEvent( 'on'+type, obj[type+fn] );
	} else if(obj.addEventListener) {			
		obj.addEventListener( type,fn, false );
	} else {
		var originalHandler = obj["on" + type]; 
		if (originalHandler) { 
		  obj["on" + type] = function(e){originalHandler(e);fn(e);}; 
		} else { 
		  obj["on" + type] = fn; 
		} 
	}
}

wHELPERS.prototype.removeEvent = function(obj, type, fn) {
	if (obj.detachEvent) {
		if(obj[type+fn]) {
			obj.detachEvent( 'on'+type, obj[type+fn] );
			obj[type+fn] = null;
		}
	} else if(obj.removeEventListener)
		obj.removeEventListener( type, fn, false );
	else {
		obj["on" + type] = null;
	}
}

// Returns the event's source element 
wHELPERS.prototype.getSourceElement = function(e) {	
	if(!e) e = window.event;	
	if(e.target)
		var srcE = e.target;
	else
		var srcE = e.srcElement;
	if(!srcE) return null;
	if(srcE.nodeType == 3) srcE = srcE.parentNode; // safari weirdness		
	if(srcE.tagName.toUpperCase()=='LABEL' && e.type=='click') { 
		// when clicking a label, firefox fires the input onclick event
		// but the label remains the source of the event. In Opera and IE 
		// the source of the event is the input element. Which is the 
		// expected behavior, I suppose.		
		if(srcE.getAttribute('for')) {
			srcE = document.getElementById(srcE.getAttribute('for'));
		}
	}
	return srcE;
}

// Cancel the default execution of an event.
wHELPERS.prototype.preventEvent = function(e) {
	if (!e) e = window.event;
	if (e.preventDefault) e.preventDefault();
	else e.returnValue = false;
	return false;
}

// Cancel the propagation of the event
wHELPERS.prototype.stopPropagation = function(e) {
	if (!e) var e = window.event;
	e.cancelBubble = true;
	if (e.stopPropagation) e.stopPropagation();
}

// Generates a random ID
wHELPERS.prototype.randomId = function () {
	var seed = (new Date()).getTime();
	seed = seed.toString().substr(6);
	for (var i=0; i<6;i++)
		seed += String.fromCharCode(48 + Math.floor((Math.random()*10)));
	return "id-" + seed;
}

// Activating an Alternate Stylesheet (thx to: http://www.howtocreate.co.uk/tutorials/index.php?tut=0&part=27)
// Use this to activate a CSS Stylesheet that shouldn't be used if javascript is turned off.
// The stylesheet rel attribute should be 'alternate stylesheet'. The title attribute MUST be set.
wHELPERS.prototype.activateStylesheet = function(sheetref) {
	i