我无法理解代码的执行

Question

my code: 我的代码：

<head>
     <!-- All the required scripts and CSS -->
    <link rel="stylesheet" href="http://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css">

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
    <script src="http://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>
    <script type="text/javascript" src="http://www.parsecdn.com/js/parse-1.1.14.min.js"></script>
</head>

<body>
    <!-- Bootstrap nav-tabs -->
    <ul class="nav nav-tabs" id="mainTabs">
        <li class="active" ><a href="#home" data-toggle="tab"><span class="glyphicon glyphicon-home"></span> Home</a></li>
        <li><a href="#group" data-toggle="tab" >Groups</a></li>
    </ul>

    <!-- Content of nav-tabs -->    
    <div class="tab-content" id="myTabContent">
        <div class="tab-pane fade active in" id="home">
            home
        </div>

        <div class=" fade tab-pane" id="group" >
            <div class="container">
                <div class="row">
                    <div class="col-xs-12 col-md-12">
                        <h4>Groups</h4>
                        <button onclick="f5()"> Add Group</button>

                    </div>
                </div>
            </div>
        </div>
    </div>

    <!-- Bootstrap Model -->
    <div class="modal fade" id="myModal2">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                      <span aria-hidden="true">&times;</span>
                    </button>
                    <h4 class="modal-title" >Add New Group</h4>
                </div>
                <div class="modal-body">
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-default" data-dismiss="modal">Cancel</button>
                    <button type="button" class="btn btn-primary btn-md" id="add" >Add</button> 
                </div>
            </div><!-- /.modal-content -->
        </div><!-- /.modal-dialog -->
    </div><!-- /.modal -->

    <script type="text/javascript">         

    function f5() { 
        $('#myModal2').modal('show');
        $('#myModal2').on('click','#add', function (e) {
            console.log("new clicked");
            $('#myModal2').modal('hide');
        });
    }

    </script>

</body>

Now the problem is: 现在的问题是：
when I click on model button with id "add" first time then: 当我第一次单击ID为“ add”的模型按钮时：

Output: new clicked (printed one time) 输出：新点击（打印一次）

when I click on model button with id "add" again: 当我再次单击ID为“ add”的模型按钮时：

Now, Output: new clicked (printed two times) 现在，输出：单击新（打印两次）

when I click on model button with id "add" again: 当我再次单击ID为“ add”的模型按钮时：

Now, Output: new clicked (printed three times) 现在，输出：单击新（打印三遍）

when I click on model button with id "add" again: 当我再次单击ID为“ add”的模型按钮时：

Now, Output: new clicked (printed four times) 现在，输出：单击新（打印四次）

Why it is happening?? 为什么会这样？ I have searched on stack overflow and google but can't find anything useful to me. 我已经搜索了堆栈溢出和Google，但是找不到对我有用的东西。 I am new to bootstrap, what I want is that each time that button with id "add" is clicked "new clicked" should be printed one time only. 我是Bootstrap的新手，我想要的是每次单击ID为“ add”的按钮时，“ new clicked”都应仅打印一次。

Answer 1

You would want to check the .off method form jQuery. 您可能想检查jQuery的.off方法。 It seems that you´re adding multiple listeners for the same thing, and you may want to remove all of them, before reassigning to avoid multiple prints of the same message. 似乎您要为同一事物添加多个侦听器，并且您可能想要删除所有侦听器，然后再重新分配以避免同一消息的多个打印。

For instance, in your f5 function (please, from now on use clear function for code clarity purposes) you´re creating a new listener for the same element, each time you execute it. 例如，在您的f5函数中（请从现在开始，为了代码清晰起见，请使用clear函数），您每次执行该元素时都会为其创建一个新的侦听器。 .off() will help you because before attaching a new event listeners, it will remove the previously added ones. .off（）将为您提供帮助，因为在附加新的事件侦听器之前，它将删除以前添加的事件侦听器。

BUT, in order to do things in the right way, you should group you event listeners attach code in a single method like "addEventListeners()", and run that function once. 但是，为了以正确的方式执行操作，您应该将事件侦听器的代码附加到一个组中，例如“ addEventListeners（）”，然后运行一次该函数。 (If you´re adding elements to a page after loading it, then use event delegation). （如果要在加载页面后向页面添加元素，请使用事件委托）。

function f5() { 
    $('#myModal2').modal('show');
    $('#myModal2').off('click'); // will remove any previous listeners attached with on
    $('#myModal2').on('click','#add', function (e) {
        console.log("new clicked");
        $('#myModal2').modal('hide');
    });
}

Regards 问候

我无法理解代码的执行

问题描述

1 个解决方案

解决方案1
1 已采纳 2015-01-13 17:47:27

我无法理解代码的执行

问题描述

1 个解决方案

解决方案1 1 已采纳 2015-01-13 17:47:27

解决方案1
1 已采纳 2015-01-13 17:47:27