可以防止重复提交的问题

例如
                                document.forms[0].onsubmit=function () {
                                   if (window.document.readyState != null &&
                                            window.document.readyState != 'complete')
                                    {
                                        alert("正在处理，请稍候！");
                                        return false;
                                    }
                                  else
                                  { 
                                          return true;
                                   }
                               }

关键就是红色的那段