function Checkfields()
{
		if (document.lexchange.nombre_sitio.value == ""){
			alert("Please enter the SITE NAME");
			return false;}
			
		if (document.lexchange.url_sitio.value == ""){
			alert("Please enter the SITE URL");
			return false;}
			
		if (document.lexchange.url_reciproco.value == ""){
			alert("Please enter the RECIPROCAL URL");
			return false;}
			
		if (document.lexchange.nombre_contacto.value == ""){
			alert("Please enter the CONTACT NAME");
			return false;}
			
		if (document.lexchange.localizacion.value == ""){
			alert("Please enter the LOCATION OF THE COMPANY");
			return false;}
			
		if (document.lexchange.descripcion.value == ""){
			alert("Please enter the SITE DESCRIPTION");
			return false;}
			
		if (document.lexchange.email.value == ""){
			alert("Please enter a valid E-Mail");
			return false;}
		else {
			if (/^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(document.contacto.email.value)){
		   return (true)
		  } else {
		   alert("Your E-mail address is not valid");
		   return (false);
		  }
		}
}