jQuery中關於​​bind()函數詳解

<span style='font-size: 14px; font-family: 微软雅黑, "Microsoft YaHei";'>相信很多接觸過jQuery的小夥伴對bind()函數一點都不陌生吧，但是很多小夥伴還不是很清bind()的意義與使用，bind()</span> 函數用來為每個符合元素的一個或多個事件綁定事件處理函數、今天我們就帶大家詳細介紹下jQuery中關於​​bind()函數詳解！

此外，你還可以額外傳遞給事件處理函數一些所需的資料。

執行bind()時，事件處理函數會綁定到每個符合元素上。因此你使用bind()所有button元素綁定了click事件，是為當時文件中存在的每個button元素綁定click事件。如果之後你在文件中加入了新的button元素，綁定事件不會對其生效。如果你希望綁定事件對未來新加入的元素也生效，請使用on()、delegate()、live()等事件函數(盡量優先使用靠前的事件函數)。

此外，你可以為相同元素、相同事件類型綁定多個事件處理函數。觸發事件時，jQuery會依照綁定的先後順序依序執行綁定的事件處理函數。

要刪除透過bind()綁定的事件，請使用unbind()函數。

該函數屬於jQuery物件(實例)。

語法

bind()函數主要有以下兩種形式的用法：

用法一：

jQueryObject.bind( events [, data ], handler )

用法二：jQuery 1.4.3 新增支援該用法。

jQueryObject.bind( events [, data ] [, isDefaultBubble ] )

用法三：jQuery 1.4 新增支援該用法。

jQueryObject.bind( eventsMap )

參數

參數	描述
#events	String類型一個或多個用空格分隔的事件類型和可選的命名空間，例如"click"、"focus click"、"keydown.myPlugin"。
data	可選/任意型別觸發事件時，需要透過event.data傳遞給事件處理函數的任意資料。
handler	Function類型指定的事件處理函數。
isDefaultBubble	可選/Boolean類型指定觸發事件時，是否允許元素的預設行為和事件冒泡。預設為true。
eventsMap	Object類型一個Object物件，其每個屬性對應事件類型和可選的命名空間(參數events)，屬性值對應綁定的事件處理函數(參數handler)。

#

关于参数events中可选的命名空间(1.4.3+才支持)，请参考最下面的示例代码。

参数handler中的this指向当前DOM元素。bind()还会为handler传入一个参数：表示当前事件的Event对象。

参数handler的返回值与DOM原生事件的处理函数返回值作用一致。例如submit(表单提交)事件的事件处理函数返回false，可以阻止表单的提交。

参数isDefaultBubble用于指示是否允许元素的默认行为和事件冒泡。如果该值为false，它将阻止元素的默认行为(例如：触发click事件的链接的默认跳转行为，触发submit事件的表单的默认提交行为)和事件的冒泡传递。

返回值

bind()函数的返回值为jQuery类型，返回当前jQuery对象本身。

示例&说明

以点击事件("click")为例，以下是jQuery中事件函数的常规用法(某些函数也存在其它形式的用法，此处暂不列出)：

<span class="com">// 这里的选择器selector用于指定可以触发事件的元素<span class="pln"><br/>// 这里的选择器ancestor应是selector的祖辈元素，selector触发的事件可以被其祖辈元素在事件流中捕获，从而以"委托代理"的形式触发事件。<span class="pln"><br/><br/>// jQuery 1.0+ (1.4.3+支持参数data)<span class="pln"><br/>$<span class="pun">(<span class="str">"selector"<span class="pun">).<span class="pln">click<span class="pun">(<span class="pln"> <span class="pun">[<span class="pln"> data <span class="pun">,]<span class="pln"> handler <span class="pun">);<span class="pln"><br/><br/>// jQuery 1.0+ (1.4.3+支持参数data)<span class="pln"><br/>$<span class="pun">(<span class="str">"selector"<span class="pun">).<span class="pln">bind<span class="pun">(<span class="pln"> <span class="str">"click"<span class="pln"> <span class="pun">[,<span class="pln"> data <span class="pun">],<span class="pln"> handler <span class="pun">);<span class="pln"><br/><br/>// jQuery 1.3+ (1.4+支持参数data)<span class="pln"><br/>$<span class="pun">(<span class="str">"selector"<span class="pun">).<span class="pln">live<span class="pun">(<span class="pln"> <span class="str">"click"<span class="pln"> <span class="pun">[,<span class="pln"> data <span class="pun">],<span class="pln"> handler <span class="pun">);<span class="pln"><br/><br/>// jQuery 1.4.2+<span class="pln"><br/>$<span class="pun">(<span class="str">"ancestor"<span class="pun">).<span class="pln">delegate<span class="pun">(<span class="pln"> <span class="str">"selector"<span class="pun">,<span class="pln"> <span class="str">"click"<span class="pln"> <span class="pun">[,<span class="pln"> data <span class="pun">],<span class="pln"> handler <span class="pun">);<span class="pln"><br/><br/>// jQuery 1.7+<span class="pln"><br/>$<span class="pun">(<span class="str">"ancestor"<span class="pun">).<span class="pln">on<span class="pun">(<span class="pln"> <span class="str">"click"<span class="pun">,<span class="pln"> <span class="str">"selector"<span class="pln"> <span class="pun">[,<span class="pln"> data <span class="pun">],<span class="pln"> handler <span class="pun">);</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

请参考下面这段初始HTML代码：

<span class="tag"><p<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n1"<span class="tag">><span class="pln"><br/>    <span class="tag"><p<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n2"<span class="tag">><span><span class="pln">CodePlayer<span class="tag"></span></p><span class="pln"><br/>    <span class="tag"><p<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n3"<span class="tag">><span><span class="pln">专注于编程开发技术分享<span class="tag"></span></p><span class="pln"><br/>    <span class="tag"><em<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n4"<span class="tag">><span class="pln">http://www.365mini.com<span class="tag"></em><span class="pln"><br/></p><span class="pln"><br/><p<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n5"<span class="tag">><span class="pln">Google<span class="tag"></p></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

我们为e388a4556c0f65e1904146cc1a846bee中的所有e388a4556c0f65e1904146cc1a846bee元素绑定点击事件：

<span class="com">//为p中的所有p元素的click事件绑定事件处理函数<span class="pln"><br/>//只有n2、n3可以触发该事件<span class="pln"><br/>$<span class="pun">(<span class="str">"p p"<span class="pun">).<span class="pln">bind<span class="pun">(<span class="str">"click"<span class="pun">,<span class="pln"> <span class="kwd">function<span class="pun">(){<span class="pln"><br/>// 这里的this指向触发点击事件的p元素(Element)<span class="pln"><br/>    alert<span class="pun">(<span class="pln"> $<span class="pun">(<span class="kwd">this<span class="pun">).<span class="pln">text<span class="pun">()<span class="pln"> <span class="pun">);<span class="pln"><br/>});</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

运行代码(以下代码请自行复制到演示页面运行)

此外，我们还可以同时绑定多个事件，并为事件处理函数传递一些附加的数据，我们可以通过jQuery为事件处理函数传入的参数event(Event事件对象)来进行处理：

<span class="kwd">var<span class="pln"> obj <span class="pun">=<span class="pln"> <span class="pun">{<span class="pln"> id<span class="pun">:<span class="pln"> <span class="lit">5<span class="pun">,<span class="pln"> name<span class="pun">:<span class="pln"> <span class="str">"王五"<span class="pln"> <span class="pun">};<span class="pln"><br/><br/>//为n5绑定mouseenter mouseleave两个事件，并为其传入附加数据obj<span class="pln"><br/>// 附加数据可以是任意类型<span class="pln"><br/>$<span class="pun">(<span class="str">"#n5"<span class="pun">).<span class="pln">bind<span class="pun">(<span class="str">"mouseenter mouseleave"<span class="pun">,<span class="pln"> obj<span class="pun">,<span class="pln"> <span class="kwd">function<span class="pun">(<span class="pln">event<span class="pun">){<span class="pln"><br/>    <span class="kwd">var<span class="pln"> $me <span class="pun">=<span class="pln"> $<span class="pun">(<span class="kwd">this<span class="pun">);<span class="pln"><br/>    <span class="kwd">var<span class="pln"> obj <span class="pun">=<span class="pln"> event<span class="pun">.<span class="pln">data<span class="pun">;<span class="pln"> <span class="com">// 这就是传入的附加数据<span class="pln"><br/>    <span class="kwd">if<span class="pun">(<span class="pln"> event<span class="pun">.<span class="pln">type <span class="pun">==<span class="pln"> <span class="str">"mouseenter"<span class="pun">){<span class="pln"><br/>        $me<span class="pun">.<span class="pln">html<span class="pun">(<span class="pln"> <span class="str">"你好，"<span class="pln"> <span class="pun">+<span class="pln"> obj<span class="pun">.<span class="pln">name <span class="pun">+<span class="pln"> <span class="str">"!"<span class="pun">);<span class="pln"><br/>    <span class="pun">}<span class="kwd">else<span class="pln"> <span class="kwd">if<span class="pun">(<span class="pln">event<span class="pun">.<span class="pln">type <span class="pun">==<span class="pln"> <span class="str">"mouseleave"<span class="pln"> <span class="pun">){<span class="pln"><br/>        $me<span class="pun">.<span class="pln">html<span class="pun">(<span class="pln"> <span class="str">"再见，"<span class="pln"> <span class="pun">+<span class="pln"> obj<span class="pun">.<span class="pln">name <span class="pun">+<span class="pln"> <span class="str">"!"<span class="pun">);<span class="pln">      <br/>    <span class="pun">}<span class="pln">           <br/><span class="pun">}<span class="pln"> <span class="pun">);</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

此外，如果符合条件的元素是bind()函数执行后新添加的，绑定事件不会对其生效。同样以初始HTML代码为例，我们可以编写如下jQuery代码：

<span class="com">//为p中的所有p元素的click事件绑定事件处理函数<span class="pln"><br/>//只有n2、n3可以触发该事件<span class="pln"><br/>$<span class="pun">(<span class="str">"p p"<span class="pun">).<span class="pln">bind<span class="pun">(<span class="str">"click"<span class="pun">,<span class="pln"> <span class="kwd">function<span class="pun">(<span class="pln">event<span class="pun">){<span class="pln"><br/>    alert<span class="pun">(<span class="pln"> $<span class="pun">(<span class="kwd">this<span class="pun">).<span class="pln">text<span class="pun">()<span class="pln"> <span class="pun">);<span class="pln"><br/>});<span class="pln"><br/><br/>// 新添加的n6不会触发上述click事件<span class="pln"><br/>$<span class="pun">(<span class="str">"#n1"<span class="pun">).<span class="pln">append<span class="pun">(<span class="str">&#39;<p id="n6">上述绑定的click事件不会对该元素也生效!</p>&#39;<span class="pun">);</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

参数events还支持为事件类型附加额外的命名空间。当为同一元素绑定多个相同类型的事件处理函数时。使用命名空间，可以在触发事件、移除事件时限定触发或移除的范围。

<span class="kwd">function<span class="pln"> clickHandler<span class="pun">(<span class="pln">event<span class="pun">){<span class="pln"><br/>    alert<span class="pun">(<span class="pln"> <span class="str">"触发时的命名空间:["<span class="pln"> <span class="pun">+<span class="pln"> event<span class="pun">.<span class="pln">namespace <span class="pun">+<span class="pln"> <span class="str">"]"<span class="pun">);<span class="pln"><br/>}<span class="pln"><br/><br/>var<span class="pln"> $p <span class="pun">=<span class="pln"> $<span class="pun">(<span class="str">"p"<span class="pun">);<span class="pln"><br/><br/>// A：为所有p元素绑定click事件，定义在foo和bar两个命名空间下<span class="pln"><br/>$p<span class="pun">.<span class="pln">bind<span class="pun">(<span class="pln"> <span class="str">"click.foo.bar"<span class="pun">,<span class="pln"> clickHandler <span class="pun">);<span class="pln"><br/><br/>// B：为所有p元素绑定click事件，定义在test命名空间下<span class="pln"><br/>$p<span class="pun">.<span class="pln">bind<span class="pun">(<span class="pln"> <span class="str">"click.test"<span class="pun">,<span class="pln"> clickHandler <span class="pun">);<span class="pln"><br/><br/>var<span class="pln"> $n2 <span class="pun">=<span class="pln"> $<span class="pun">(<span class="str">"#n2"<span class="pun">);<span class="pln"><br/><br/>// 触发所有click事件<span class="pln"><br/>$n2<span class="pun">.<span class="pln">trigger<span class="pun">(<span class="str">"click"<span class="pun">);<span class="pln"> <span class="com">// 触发A和B (event.namespace = "")<span class="pln"><br/><br/>// 触发定义在foo命名空间下的click事件<span class="pln"><br/>$n2<span class="pun">.<span class="pln">trigger<span class="pun">(<span class="str">"click.foo"<span class="pun">);<span class="pln"> <span class="com">// 触发A (event.namespace = "foo")<span class="pln"><br/>// 触发定义在bar命名空间下的click事件<span class="pln"><br/>$n2<span class="pun">.<span class="pln">trigger<span class="pun">(<span class="str">"click.bar"<span class="pun">);<span class="pln"> <span class="com">// 触发A (event.namespace = "bar")<span class="pln"><br/>// 触发同时定义在foo和bar两个命名空间下的click事件<span class="pln"><br/>$n2<span class="pun">.<span class="pln">trigger<span class="pun">(<span class="str">"click.foo.bar"<span class="pun">);<span class="pln"> <span class="com">// 触发A (event.namespace = "bar.foo")<span class="pln"><br/><br/>// 触发定义在test命名空间下的click事件<span class="pln"><br/>$n2<span class="pun">.<span class="pln">trigger<span class="pun">(<span class="str">"click.test"<span class="pun">);<span class="pln"> <span class="com">// 触发B (event.namespace = "test")</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

bind()函数的参数eventsMap是一个对象，可以"属性-值"的方式指定多个"事件类型-处理函数"。对应的示例代码如下：

var eventsMap = {
    "mouseenter": function(event){
        $(this).html( "Hello!");        
    },
    
    "mouseleave": function(event){
        $(this).html( "Bye!");
    }
};

//为n5绑定mouseenter mouseleave两个事件
$("#n5").bind( eventsMap );

总结：

本文使用示例代码详细的为大家分析了jQuery中关于bind()函数，相信大家对此也是有了进一步的了解，希望对你的工作有所帮助！

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