function tildes(cad){		
	cad = String(cad)
	cad = cad.replace("á","a'");
	cad = cad.replace("Á","A'");
	cad = cad.replace("é","e'");
	cad = cad.replace("É","E'");
	cad = cad.replace("í","i'");				
	cad = cad.replace("Í","I'");
	cad = cad.replace("ó","o'");		
	cad = cad.replace("Ó","O'");		
	cad = cad.replace("ú","u'");
	cad = cad.replace("Ú","U'");		
	cad = cad.replace("ñ","n'");		
	cad = cad.replace("Ñ","N'");		
	return cad;
}


//1.- Primero se crea el objeto Ajax, instanciando el objeto XMLHttpRequest para los distintos navegadores

function ajaxFunction() {
	var xmlHttp;
	try {
	// Firefox, Opera 8.0+, Safari
	xmlHttp=new XMLHttpRequest();
	return xmlHttp;
	} catch (e) {
	// Internet Explorer
		try {
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
			return xmlHttp;
		} catch (e) {
			try {
				xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
				return xmlHttp;
			} catch (e) {
		alert("Tu navegador no soporta AJAX!");
	return false;
			}		
		}	
	}
}

//2.-Se crea la función para llamar a la página de manera asíncrona y cargarla en la capa que le indiquemos
function AJAX_Enviar(_pagina,capa) {
	var ajax;

	ajax = ajaxFunction();
	ajax.open("POST", _pagina, true);

	ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
	ajax.setRequestHeader("Content-Type","text/html; charset=utf-8");
	ajax.setRequestHeader("Content-Language","es");

	ajax.onreadystatechange = function()
	{
		if (ajax.readyState == 4)
		{
			if (ajax.status==200)
			{
				document.getElementById(capa).innerHTML = ajax.responseText;
			}
		}
	}
	ajax.send(null);
}


function AJAX_enviarFormulario(_pagina,formid,capa){
	var ajax
	ajax = ajaxFunction()
	var Formulario = document.getElementById(formid)
	var longitudFormulario = Formulario.elements.length
	var cadenaFormulario = ""
	var sepCampos
	sepCampos = ""
	for (var i=0; i <= Formulario.elements.length-1;i++) {
		if (Formulario.elements[i].type == 'checkbox') {
			if (Formulario.elements[i].checked==true)
				cadenaFormulario += sepCampos+Formulario.elements[i].name+'='+encodeURI(Formulario.elements[i].value)
		} else				
			cadenaFormulario += sepCampos+Formulario.elements[i].name+'='+encodeURI(Formulario.elements[i].value)
	
		 sepCampos="&"
	}
	ajax.open("POST", _pagina+'?'+cadenaFormulario , true)
  	ajax.setRequestHeader("Content-Type","application/x-www-form-urlencoded")
	ajax.onreadystatechange = function () {
  	if (ajax.readyState == 4 &&  ajax.status==200)  
		document.getElementById(capa).innerHTML = ajax.responseText
	}
	ajax.send(null)
}