function mostrar(layer_ref){
	var state='block';
	if (document.all) { //IS IE 4 or 5 (or 6 beta)
	eval( "document.all." + layer_ref + ".style.display = state");
	}
	if (document.layers) { //IS NETSCAPE 4 or below
	document.layers[layer_ref].display = state;
	}
	if (document.getElementById &&!document.all) {
	hza = document.getElementById(layer_ref);
	hza.style.display = state;		
	}	
}
function trim(s) {
	return s.replace( /^\s*/, "" ).replace( /\s*$/, "" );
}
function ocultar(layer_ref){

	var state='none';
	
	if (document.all) { //IS IE 4 or 5 (or 6 beta)
	eval( "document.all." + layer_ref + ".style.display = state");
	}
	if (document.layers) { //IS NETSCAPE 4 or below
	document.layers[layer_ref].display = state;
	}
	if (document.getElementById &&!document.all) {
	hza = document.getElementById(layer_ref);
	hza.style.display = state;
	}
}	

function validarEmail(email){
	
	var arroba="@"
	var punto="."
	var larroba=email.indexOf(arroba)
	var lemail=email.length
	var lpunto=email.indexOf(punto)
	if (email.indexOf(arroba)==-1){		  
	   return false
	}

	if (email.indexOf(arroba)==-1 || email.indexOf(arroba)==0 || email.indexOf(arroba)==lemail){		  
	   return false
	}

	if (email.indexOf(punto)==-1 || email.indexOf(punto)==0 || email.indexOf(punto)==lemail){		   
	    return false
	}

	 if (email.indexOf(arroba,(larroba+1))!=-1){		  
	    return false
	 }
	 if (email.substring(larroba-1,larroba)==punto || email.substring(larroba+1,larroba+2)==punto){		   
	    return false
	 }
	 if (email.indexOf(punto,(larroba+2))==-1){		   
	    return false
	 }		
	 if (email.indexOf(" ")!=-1){		    
	    return false
	 }

		 return true	

}