var req;
function loadXMLDoc(url) 
{
	// branch for native XMLHttpRequest object
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = processReqChange;
        req.open("GET", url, true);
        req.send(null);
    // branch for IE/Windows ActiveX version
    } else if (window.ActiveXObject) {
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
			req.onreadystatechange = processReqChange;
            req.open("GET", url, true);
            req.send();
        }
    }
}

function processReqChange() 
{
	
	// only if req shows "complete"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            // ...processing statements go here...
			response  = req.responseXML.documentElement;
 			parseFormXml();	
        } else {
            alert("There was a problem retrieving the XML data:\n" + req.statusText);
        }
    }
}


/* From scottandrew.com via simon.incutio.com */
function addEvent(obj, evType, fn, useCapture){
  if (obj.addEventListener) {
    obj.addEventListener(evType, fn, useCapture);
    return true;
  } else if (obj.attachEvent){
    var r = obj.attachEvent("on"+evType, fn);
    return r;
  } else {
    // alert('Handler could not be attached');
    return false;
  }
}

//called when xml document is imported*/
function parseFormXml()
{
	form = document.getElementById(response.attributes[0].nodeValue);	
	//onsubmit, form is checked
	addEvent(form, 'submit', checkForm, false);
	validators = new Array();
	elements = response.getElementsByTagName('element');
//create element validator objects and add to array
	for (var i = 0; i < elements.length; i++)
	{
		val = new ElementValidator(elements[i]);
		validators[val.id] = val;
		//onblur check validity
		addEvent(val.element, 'change', onblurCheck, false);
	}
}

function checkForm(event)
{
	var pass = true;
	for (var i in validators)
	{
		validators[i].check();
		if(validators[i].valid == false)
		{
			pass = false;
		}
	}
	if (pass == false)
	{
		message = 'You have not completed this form correctly.\n';
		message += 'Please go back and review your answers.';
		alert(message);
		//stop form submittal
		//ie event model
		if(document.all)
		{
			event.returnValue = false;
		}
		//standard w3c model - moz
		else
		{
			event.preventDefault();
		}
	}
}

function onblurCheck(event)
{
	//ie
	if(document.all)
	{
		id = event.srcElement.getAttribute('id');
	}
	//moz
	else
	{
		id = this.getAttribute('id');
	}
	validators[id].check();
}


//Element Validator object
function ElementValidator(node)
{
	this.id = node.getAttribute('id');
	this.element = document.getElementById(this.id);
	this.valid = true;
	this.min = node.getAttribute('min');
	this.max = node.getAttribute('max');
	this.req = node.getAttribute('req') == "true";
	this.regs = new Array();
	regexes = node.getElementsByTagName('regex');
	for (var i = 0; i < regexes.length; i++ )
	{
		//grab text inside regex tag(s)
		this.regs[i] = new RegExp(regexes[i].childNodes[0].nodeValue);
	}
	err = node.getElementsByTagName('error')[0];
	if (err != null)
	{
		this.error = err.childNodes[0].nodeValue;
	}
	else
	{
		this.error = null;
	}
	this.name = node.getAttribute('name');
	this.sameAs = node.getAttribute('sameas');
	//get reference to element node that value should equal
	if (this.sameAs != null)
	{
		this.sameAs = document.getElementById(this.sameAs);
	}
	//classname of enclosing <li>
	this.parentClass = this.element.parentNode.className;
	
	this.check = function()
  {
   	//confirmation value. must be same as confirming value + valid for
		//confirming value's rules
   	if (this.sameAs != null)
   	{
   		if (this.element.value == this.sameAs.value)
   		{
				if(validators[this.sameAs.getAttribute('id')].valid == true)
				{
	   			this.makeValid();
				}
				else
				{
					var otherName = validators[this.sameAs.getAttribute('id')].name;
					this.makeInvalid('Your ' + otherName + ' is not correct.');
				}
   		}
   		else
   		{
				var otherName = validators[this.sameAs.getAttribute('id')].name;
				var msg = 'This value must be identical to your ' + otherName + '.';
   			this.makeInvalid(msg);
   		}
   	}
   	else
   	{
   		var val = this.element.value;
   		//first check for required
   		if(this.req && val == "")
   		{
   			this.makeInvalid(this.reqErrMsg());
   			return;
   		}
			//if not required and no value, is valid
			else if((this.req == false) && (val == ""))
			{
				this.makeValid();
				return;
			}
   		//check for length
   		if((this.min != null && val.length < this.min) ||
   			(this.max != null && val.length > this.max))
   		{
   			this.makeInvalid(this.lenErrMsg());
   			return;
   		}
   		//check that it matches at least one supplied regex, if any supplied
   		if(this.regs.length > 0)
   		{
   			var pass = false;
   			for (var i = 0; i < this.regs.length; i++)
   			{
   				if (this.regs[i].test(val))
   				{
   					pass = true;
   					break;
   				}
   			}
   			if (pass == false)
   			{
   				this.makeInvalid(this.error);
   				return;
   			}
   		}
   		//passed all tests
   		this.makeValid();
   	}
  }
	
	this.lenErrMsg = function ()
	{
		var cap = this.name.substring(0,1).toUpperCase();
		var capName = cap + this.name.substring(1, this.name.length);
		if (this.min != null && this.max != null)
		{
			ret = capName + ' must be between ' + this.min + ' and ';
			ret += this.max +  ' characters.';
			return ret;
		}
		else if (this.min != null)
		{
			return capName + ' must be more than ' + this.min + ' characters.';
		}
		else //max, no min
		{
			return capName + ' must be less than ' + this.max + ' characters.';
		}
	}
	
	this.reqErrMsg = function()
  {
  	letter = this.name.substring(0, 1);
  	switch (letter)
  	{
  	case 'a':
  	case 'e':
  	case 'i':
  	case 'o':
  	case 'u':
  		word = 'an';
  		break;
  	default:
  		word = 'a';
  		break;
  	}
  	return 'You must supply ' + word + ' ' + this.name + '.';
  }
	
	this.makeInvalid = function(errMsg)
  {
	this.element.parentNode.className = this.parentClass + " error";
  	//insert error message
  	//if already invalid will have an error message already
  	if (this.valid == false)
  	{
  		errorNode = document.getElementById(this.id + 'errmsg');
  		textNode = document.createTextNode(errMsg);
  		//childnodes[0] is the old error text
  		errorNode.replaceChild(textNode, errorNode.childNodes[0]);
  	}
  	else
  	{
  		//create and add to <li> a span with an error message
  		span = document.createElement('span');
  		span.className = "errormsg";
  		span.setAttribute("id", this.id + "errmsg");
  		textNode = document.createTextNode(errMsg);
  		span.appendChild(textNode);
  		this.element.parentNode.appendChild(span);
		this.element.className ="errorf";
  	}
  	this.valid = false;
  }
	
	this.makeValid = function()
  {
  	//remove error message if there
  	if(this.valid == false)
  	{
  		errorNode = document.getElementById(this.id + 'errmsg');
  		this.element.parentNode.removeChild(errorNode);
		
  	}
	this.element.className ="";
  	this.valid = true;
  	this.element.parentNode.className = this.parentClass;
  }
}