Question

我有这个代码：我的第一个验证是我试图检查用户名是否为null然后我有一个ajax验证，验证用户名是否已经存在。但是，当我尝试在回调函数中分配我的变量时，我指定的值不起作用..

isValid初始值为true ..如果username存在，我想在其上分配false ..但值不会改变..

当我尝试console.log(isValid)时，它仍然是真的..在此先感谢..

function validateStep1(){
       var isValid = true; 
       // Validate Username
       var un = $('#username').val();
       if(!un && un.length <= 0){
         isValid = false;
         $('#msg_username').html('(Please fill username)').show();
       }else{
           //username ajax validation
           var $check_username;
           var $form = $('#create_user_form').data('url');
           var $url = $form + "employee_c/username_validation";
           $.when(ajax_validation($url,un)).done(function(){
              if(_gbValidateSuccess){
                 $('#msg_username').html('(Username is already existing!)').show();
                 isValid = false;
              }else{
                $('#msg_username').html('').hide();
              }
           });
       }
     console.log(isValid); //still true.. but should be false instead..
}

Answer 1

使用Promise，它非常简单，非常适合异步调用（下载并包含promise js）

-module(macro_mod_names).

-define(SERVER, ?MODULE). % Oh, god! Why??
-define(TM, another_module).

-export([bad/1, good/1]).

bad(Arg) ->
  Parsed = gen_server:call(?SERVER, {parse, Arg}),
  ?TM:handle(Parsed).

good(Arg) ->
  Parsed = gen_server:call(?MODULE, {parse, Arg}),
  another_module:handle(Parsed).

//为promise js添加此代码

 function validateStep1(){
      return new Promise(function (resolve, reject) {
       var un = $('#username').val();
           if(!un && un.length <= 0){
             reject(); // it will return false
             $('#msg_username').html('(Please fill username)').show();
           }else{
               //username ajax validation
               var $check_username;
               var $form = $('#create_user_form').data('url');
               var $url = $form + "employee_c/username_validation";
               $.when(ajax_validation($url,un)).done(function(){
                  if(_gbValidateSuccess){
                     $('#msg_username').html('(Username is already existing!)').show();
                     isValid = false;
                     reject(); // it will return false
                  }else{
                    $('#msg_username').html('').hide();
                    resolve(); //it will return true
                  }
               });
           }

     });
    }

jQuery延迟赋值不起作用

1 个答案: