Question

当在下面的代码中声明时，$sessionTimeLeft在updateSession()内被访问时未定义。但是当我在$sessionTimeLeft中移动initiate()声明和赋值时，我得到了正确的jQuery对象。我认为，由于关闭，我可以在$sessionTimeLeft内声明initiate()时访问$sessionTimeLeft。但为什么var session = (function SessionManager() { var timeLeftInMs; var timeLeftInMin; var delay; // in ms var $sessionTimeLeft = $('#dcSessionTimeLeft'); /* Set up the module by setting the timeout and delay time. */ function initiate(_timeout, _delay) { timeLeftInMin = _timeout; timeLeftInMs = timeLeftInMin * 60 * 1000; delay = _delay; // delay in ms setInterval(updateSession, delay); } function updateSession() { timeLeftInMs -= delay; timeLeftInMin = timeLeftInMs / 60000; // convert ms to min. $sessionTimeLeft.text(timeLeftInMin); } var publicAPI = { initiate: initiate }; return publicAPI; })(); session.initiate(30,1000);超出原始代码范围？

create table words
(
  id int not null auto_increment primary key,
  word varchar(255),
  index(word)
);

Answer 1

此处的问题是，当您尝试访问#dcSessionTimeLeft时，可能尚未加载$(function() { var session = (function SessionManager() { var timeLeftInMs; var timeLeftInMin; var delay; // in ms var $sessionTimeLeft = $('#dcSessionTimeLeft'); /* Set up the module by setting the timeout and delay time. */ function initiate(_timeout, _delay) { timeLeftInMin = _timeout; timeLeftInMs = timeLeftInMin * 60 * 1000; delay = _delay; // delay in ms setInterval(updateSession, delay); } function updateSession() { timeLeftInMs -= delay; timeLeftInMin = timeLeftInMs / 60000; // convert ms to min. $sessionTimeLeft.text(timeLeftInMin); } var publicAPI = { initiate: initiate }; return publicAPI; })(); session.initiate(30,1000); });。因此，确保加载它的一种方法是将代码包装在document.ready：

中

<script type="text/javascript" src="js/jquery.js"></script>
        <script>jQuery.noConflict();</script>
        <script type="text/javascript" src="js/bootstrap.min.js"></script>
        <script type="text/javascript" src="cordova.js"></script>
        <script type="text/javascript" src="js/functions.js"></script>        
        <script type="text/javascript">
        document.addEventListener("deviceready", onDeviceReady, false);
        function onDeviceReady() {
            checkConnection();
        }
        //------
        function checkConnection() {
            var networkState = navigator.connection.type;
            if(networkState==Connection.NONE){
                document.getElementById("main-content").innerHTML="<div style='text-align:center;'><img src='img/internet.png' style='max-width:100%;' /></div>";
            }
        
        }
        
        //------
         function teachers(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv4', '_self', 'location=no');
        }
        //------
        function news(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv6', '_self', 'location=no');
        }
        //------
        function jobs(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv7', '_self', 'location=no');
        }
        //------
        function estb(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv8', '_self', 'location=no');
        }
        //------
        function pro(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv9', '_self', 'location=no');
        }
        //------
       function internal(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv10', '_self', 'location=no');
        }
        //------
        function external(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv11', '_self', 'location=no');
        }
        //------
        function online(){
            var ref = cordova.InAppBrowser.open('http://ataksa.com/?p=serv12', '_self', 'location=no');
        }
        //------
        
        </script>

Answer 2

在这种情况下，封闭应该也能很好地工作。此代码无法正常工作的原因是您没有正确调用会话功能。请记住，此函数返回一个带有函数启动的对象

代码的最后一行应该是

session.initiate(30,1000);

这应该有效。为了重现我使用节点的问题。我将$ sessionTimeLeft变量更改为字符串hello并测试它是否仍可在updateSession函数中访问。我的代码是

var session = (function SessionManager() {
  var timeLeftInMs;
  var timeLeftInMin;
  var delay; // in ms
  var $sessionTimeLeft = "Hello";

  /* Set up the module by setting the timeout and delay time. */
  function initiate(_timeout, _delay) {
    timeLeftInMin = _timeout;
    timeLeftInMs = timeLeftInMin * 60 * 1000;
    delay = _delay; // delay in ms

    setInterval(updateSession, delay);
  }

  function updateSession() {
    timeLeftInMs -= delay;
    timeLeftInMin = timeLeftInMs / 60000; // convert ms to min.

    console.log($sessionTimeLeft);
  }

  var publicAPI = {
    initiate: initiate
  };

  return publicAPI;
})();

session.initiate(30,1000);

我得到的结果是

Hello
Hello
Hello
Hello
Hello

每1秒钟一次。

模块内部的Javascript范围问题

2 个答案: