function validarFormulario() {
	var ok = "si";			
	
	if (validarEmail(document.getElementById('emailCliente').value) == ''){
		ok = "no";
		document.getElementById('e_emailCliente').style.visibility = 'visible';
	}else{
		document.getElementById('e_emailCliente').style.visibility = 'hidden';
	}
	
	if (document.getElementById('nombreCliente').value == ''){
		ok = "no";
		document.getElementById('e_nombreCliente').style.visibility = 'visible';
	}else{
		document.getElementById('e_nombreCliente').style.visibility = 'hidden';
	}
	
	if (document.getElementById('textoCliente').value == ''){
		ok = "no";
		document.getElementById('e_textoCliente').style.visibility = 'visible';
	}else{
		document.getElementById('e_textoCliente').style.visibility = 'hidden';
	}
	//sacamos la respuesta
		if (ok=="si"){
				document.getElementById('boton').disabled = false;		
		}else{
				document.getElementById('boton').disabled = true;
		}	
		
	}	
		
		

	
function validarEmail(valor) {	
	var filter=/^[A-Za-z][A-Za-z0-9_]*@[A-Za-z0-9_]+\.[A-Za-z0-9_.]+[A-za-z]$/;	
	if (filter.test(valor)){
	return true;
	}else{
	return false;
	}
}


	
	
	



	
function muestra(capa,url){ 
  if(!(mstcapa=xGetElementById(capa))) return;
  if(mstcapa.style && xDef(mstcapa.style.visibility)){
  	if (mstcapa.style.visibility == 'visible'){
  		mstcapa.style.visibility='hidden';
  	}else{
  		mstcapa.style.visibility='visible';
	    lanzar(url,capa);
 	}   
   }
} 


function xGetElementById(e) {
  if(typeof(e)!='string') return e;
  if(document.getElementById) e=document.getElementById(e);
  else if(document.all) e=document.all[e];
  else e=null;
  return e;
}

function xDef() {
  for(var i=0; i<arguments.length; ++i){if(typeof(arguments[i])=='undefined') return false;}
  return true;
}


function lanzar(fichero,capa)
{		
	if(window.XMLHttpRequest) {
		objXml = new XMLHttpRequest(); // Gecko (Firefox, Moz), KHTML (Konqueror, Safari), Opera
	} else if(window.ActiveXObject) {
		objXml = new ActiveXObject("Microsoft.XMLHTTP"); // Internet Explorer		
	}					
	
	objXml.open("GET", fichero, true);  
	objXml.onreadystatechange=function() {

	if (objXml.readyState==4) {     
		document.getElementById(capa).innerHTML=objXml.responseText; 
	}
	}   		      				
	objXml.send(null);				
}