function nuevaventana(num)
{
  if (num = 1){
  	ventana=window.open("cartatfc.html","cartas tfc","width=330,height=470,top=160,left=250");}
  if (num = 2){
  	ventana=window.open("cartasparuvi.html","cartas paruvi","width=330,height=470,top=160,left=250");}
  if (num = 3){
  	ventana=window.open("sobresfcabierta.html","sobres formacion abierta","width=330,height=470,top=160,left=250");}
  if (num = 4){
  	ventana=window.open("sobresluminosos.html","sobresluminosos colours","width=330,height=470,top=160,left=250");}
  if (num = 5){
  	ventana=window.open("cartasparuvi.html","cartas paruvi","width=330,height=470,top=160,left=250");}
  if (num = 6){
  	ventana=window.open("cartasparuvi.html","cartas paruvi","width=330,height=470,top=160,left=250");}
}
  
function checkFields() {
missinginfo = "";
if (document.form.nombre.value == "") {
missinginfo += "\n     -  Nombre";
}
if (document.form.empresa.value == "") {
missinginfo += "\n     -  Empresa";
}
if ((document.form.email.value == "") || 
(document.form.email.value.indexOf('@') == -1) || 
(document.form.email.value.indexOf('.') == -1)) {
missinginfo += "\n     -  Email.Hay que poner *@*.*";
}

if (missinginfo != "") {
missinginfo ="_____________________________\n" +
"Los datos introducidos son erroneos en:\n" +
missinginfo + "\n_____________________________" +
"\nPor favor, vuelva a completarlos y envielos de nuevo!";
alert(missinginfo);
return false;
}
else return true;
}