function check_form(form, tocheck_csv)
{
  if ( typeof(check_form_msg) == "undefined" ) {
	check_form_msg='Debe rellenar todos los campos marcados con *';
  }
  var tocheck;
  if ( tocheck_csv ){
    
    tocheck=tocheck_csv.split(/\s*,\s*/);
  }
  else {
    tocheck=new Array();
  }
  //alert(tocheck_csv+"|"+tocheck.length);
  //alert(form.elements);
  for (i=0; i<tocheck.length; i++ ) {
    var el=form.elements[tocheck[i]];
    //alert(el);
    if ( el ) {
      if ( el && el.value == "" ) {
	el.focus();
	alert(check_form_msg);
	return false;
      }
    }
  }	
	
  return true;
}