function valida()
{
	if (document.forms[0].realname.value=="" || document.forms[0].realname.value=="Introduce tu nombre")
	{
		var nombre="El campo NOMBRE es obligatorio";
		return nombre;
	}
	else if (document.forms[0].email.value=="")
	{
		alert ("El campo DIRECCIÓN DE CORREO es obligatorio");
		return false;
	}
	else if (document.forms[0].comentaris.value=="")
	{
    	alert ("No ha escrito ningún mensaje");
		return false
	}
	else
	{
		document.forms[0].submit();
	}
}


//AJAX.. FUNCION CARGAR PÁGINAS
function sack(file) {
	this.xmlhttp = null;
	this.resetData = function() {
	this.method = "POST";
	this.queryStringSeparator = "?";
	this.argumentSeparator = "&";
	this.URLString = "";
	this.encodeURIString = true;
	this.execute = false;
	this.element = null;
	this.elementObj = null;
	this.requestFile = file;
	this.vars = new Object();
	this.responseStatus = new Array(2);
	};

	this.resetFunctions = function() {
		this.onLoading = function() { };
		this.onLoaded = function() { };
		this.onInteractive = function() { };
		this.onCompletion = function() { };
		this.onError = function() { };
		this.onFail = function() { };
	};

	this.reset = function() {
		this.resetFunctions();
		this.resetData();
	};

	this.createAJAX = function() {
		try 
		{
			this.xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
		} 
		catch (e1)
		{
			try
			{
				this.xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e2) 
			{
				this.xmlhttp = null;
			}
		}

		if (! this.xmlhttp)
		{
			if (typeof XMLHttpRequest != "undefined") 
			{
				this.xmlhttp = new XMLHttpRequest();
			} else
			{
				this.failed = true;
			}
		}
	};

	this.setVar = function(name, value){
		this.vars[name] = Array(value, false);
	};

	this.encVar = function(name, value, returnvars) {
		if (true == returnvars) {
			return Array(encodeURIComponent(name), encodeURIComponent(value));
		} else {
			this.vars[encodeURIComponent(name)] = Array(encodeURIComponent(value), true);
		}
	}

	this.processURLString = function(string, encode)
	{
		encoded = encodeURIComponent(this.argumentSeparator);
		regexp = new RegExp(this.argumentSeparator + "|" + encoded);
		varArray = string.split(regexp);
		for (i = 0; i < varArray.length; i++)
		{
			urlVars = varArray[i].split("=");
			if (true == encode)
			{
				this.encVar(urlVars[0], urlVars[1]);
			} else
			{
				this.setVar(urlVars[0], urlVars[1]);
			}
		}
	}

	this.createURLString = function(urlstring) 
	{
		if (this.encodeURIString && this.URLString.length)
		{
			this.processURLString(this.URLString, true);
		}

		if (urlstring)
		{
			if (this.URLString.length) 
			{
				this.URLString += this.argumentSeparator + urlstring;
			} else 
			{
				this.URLString = urlstring;
			}
		}

		// prevents caching of URLString
		this.setVar("rndval", new Date().getTime());
		
		urlstringtemp = new Array();
		for (key in this.vars) {
			if (false == this.vars[key][1] && true == this.encodeURIString)
			{
				encoded = this.encVar(key, this.vars[key][0], true);
				delete this.vars[key];
				this.vars[encoded[0]] = Array(encoded[1], true);
				key = encoded[0];
			}
			
			urlstringtemp[urlstringtemp.length] = key + "=" + this.vars[key][0];
		}
		
		if (urlstring)
		{
			this.URLString += this.argumentSeparator + urlstringtemp.join(this.argumentSeparator);
		} 
		else 
		{
			this.URLString += urlstringtemp.join(this.argumentSeparator);
		}
	}
	
	this.runResponse = function() {
		eval(this.response);
	}
	
	this.runAJAX = function(urlstring) 
	{
		if (this.failed) 
		{
		this.onFail();
		} 
		else 
		{
			this.createURLString(urlstring);
			if (this.element) 
			{
				this.elementObj = document.getElementById(this.element);
			}
			if (this.xmlhttp) 
			{
				var self = this;
				if (this.method == "GET") 
				{
					totalurlstring = this.requestFile + this.queryStringSeparator + this.URLString;
					this.xmlhttp.open(this.method, totalurlstring, true);
				}
				else 
				{
					this.xmlhttp.open(this.method, this.requestFile, true);
					try {
						this.xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded")
					} catch (e) { }
				}
	
				this.xmlhttp.onreadystatechange = function() 
				{
					switch (self.xmlhttp.readyState)
					{
						case 1:
						self.onLoading();
						break;
						case 2:
						self.onLoaded();
						break;
						case 3:
						self.onInteractive();
						break;
						case 4:
						self.response = self.xmlhttp.responseText;
						self.responseXML = self.xmlhttp.responseXML;
						self.responseStatus[0] = self.xmlhttp.status;
						self.responseStatus[1] = self.xmlhttp.statusText;
	
						if (self.execute) {
						self.runResponse();
						}
						
						if (self.elementObj) 
						{
							elemNodeName = self.elementObj.nodeName;
							elemNodeName.toLowerCase();
							if (elemNodeName == "input"
							|| elemNodeName == "select"
							|| elemNodeName == "option"
							|| elemNodeName == "textarea") {
							self.elementObj.value = self.response;
						} 
						else 
						{
							self.elementObj.innerHTML = self.response;
						}
						}
						if (self.responseStatus[0] == "200") 
						{
							self.onCompletion();
						} 
						else 
						{
							self.onError();
						}
	
						self.URLString = "";
						break;
					}
				};
	
				this.xmlhttp.send(this.URLString);
			}
		}
	};
	
	this.reset();
	this.createAJAX();
	}
	
	
	
	var enableCache = true;
	var jsCache = new Array();
	
	var dynamicContent_ajaxObjects = new Array();
	
	function ajax_showContent(divId,ajaxIndex,url)
	{
		var targetObj = document.getElementById(divId);
		targetObj.innerHTML = dynamicContent_ajaxObjects[ajaxIndex].response;
		if(enableCache)
		{
			jsCache[url] = dynamicContent_ajaxObjects[ajaxIndex].response;
		}
		dynamicContent_ajaxObjects[ajaxIndex] = false;
	
		ajax_parseJs(targetObj)
	}
	
	function ajax_parseJs(inputObj)
	{
		var jsTags = inputObj.getElementsByTagName('SCRIPT');
		for(var no=0;no<jsTags.length;no++)
		{
			eval(jsTags[no].innerHTML);
		}
	}
	
	function ajax_loadContent(divId,url)
	{
		if(enableCache && jsCache[url])
		{
			document.getElementById(divId).innerHTML = jsCache[url];
			return;
		}
	
		var ajaxIndex = dynamicContent_ajaxObjects.length;
		document.getElementById(divId).innerHTML = '<img src="imgLib/loadingAnimation.gif"/>';
		dynamicContent_ajaxObjects[ajaxIndex] = new sack();
		dynamicContent_ajaxObjects[ajaxIndex].requestFile = url; // Specifying which file to get
		dynamicContent_ajaxObjects[ajaxIndex].onCompletion = function()
		{ 
			ajax_showContent(divId,ajaxIndex,url); 
		}; // Specify function that will be executed after file has been found
		dynamicContent_ajaxObjects[ajaxIndex].runAJAX(); // Execute AJAX function


	}