<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)。
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 | 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。
bind()
函数的返回值为jQuery类型,返回当前jQuery对象本身。
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
中的所有
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">'<p id="n6">上述绑定的click事件不会对该元素也生效!</p>'<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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