function check_text(obj,method,message,obj2){
  if(!obj) return false;

  if(obj2) obj2.innerHTML = "";

  if(obj.value == "" || obj.value.length == 0) {
    switch(method) {
      case 'messagebox': alert(message);
                         break;

      case 'innertext': if(obj2) obj2.innerHTML=message;
                        break;
    }
    
    obj.focus();

    return false;
  }

  return true;
}

function check_box(objId, method,message,obj2){
  if(!objId) return false;

  if(obj2) obj2.innerHTML = "";

  var box = get_box_value(objId)
  if(box.length == 0) {

    switch(method) {
      case 'messagebox': alert(message);
                         break;
                         
      case 'innertext': if(obj2) obj2.innerHTML=message;
                        break;
    }
    //obj.focus();

    return false;
  }

  return true;
}

function get_box_value(objId){
  var box = [];

  for(i = 1;i < 7;i++){
    if(obj = document.getElementById(objId + i)) {
      if(obj.checked)
        box[box.length] = obj.value;
    }
  }

  return box;
}

function check_contact(contactId, checkId, checkId2) {
  var checkEl = document.getElementById(checkId);
  var check2El = document.getElementById(checkId2);

  if(checkEl.checked || check2El.checked) {
    return check_text(document.getElementById(contactId),'messagebox','請輸入邀請人姓名');
  }

  return true;
}

function check_form() {
  var check = false;

  check = check_text(document.getElementById('company_name'),'messagebox','請輸入公司名稱') &&
          check_text(document.getElementById('user_name'),'messagebox','請輸入姓名') &&
          check_text(document.getElementById('tel_1'),'messagebox','請輸入公司電話') &&
          check_text(document.getElementById('cellphone_1'),'messagebox','請輸入手機') &&
          check_text(document.getElementById('address_1'),'messagebox','請輸入公司地址') &&
          check_text(document.getElementById('email_1'),'messagebox','請輸入 Email') &&
          check_box('showing','messagebox','請選擇報名課程') &&
          check_box('source','messagebox','請選擇報名訊息來源') &&
          check_contact('source5', 'source4', 'source3');

  if(check)
    document.getElementById('chk_script').value='script_is_ok';
  return check;

}