jquery之wrap(),wrap(),unwrap()方法详解

wrap()：为每个匹配元素外面添加指定的HTML结构，

wrapAll(): 为所有匹配元素（作为一个整体）外面添加一个指定的HTML结构wrap()函数用于在每个匹配元素外部包裹指定的HTML结构。

与该函数相对的是unwrap()函数，用于当前匹配元素的父元素(只移除父元素，其内部节点全部保留)。

该函数属于<a href="http://www.php.cn/wiki/1495.html" target="_blank">jQuery</a>对象(实例)。

语法

jQueryObject.wrap( wrapper )

参数

参数	描述
wrapper	String/Element/jQuery/Function类型用于包裹匹配元素的节点。

如果参数wrapper为字符串，则将其视作jQuery选择器或html字符串，jQuery会自行判断。

jQuery 1.4 新增支持：参数wrapper可以为函数。wrap()将根据匹配的所有元素遍历执行该函数，函数中的this将指向对应的DOM元素。

wrap()还会为函数传入一个参数，即当前元素在匹配元素中的索引。函数的返回值就是用于包裹的节点内容(可以是html字符串、DOM元素或jQuery对象)。

注意：如果wrapper匹配多个元素，则只将第一个元素作为包裹元素。

注意：如果wrapper是多层嵌套的元素(例如)，wrap()将从外往内检查每层嵌套的第一个节点。如果该节点没有子节点或者第一个子节点不是Element节点(比如文本节点、注释节点等)，就停止向内查找，直接在当前节点内部的末尾位置追加(append())当前匹配元素。

返回值

wrap()函数的返回值为jQuery类型，返回当前jQuery对象本身(以便于进行链式风格的编程)。

注意：即使wrapper元素是当前页面中的元素，该元素也不会从原位置上消失。因为wrap()使用的是该元素的副本(克隆)来充当包裹。

示例&说明

wrap()函数用于在每个匹配元素之前的位置插入内容：

<span class="tag"><p><span class="pln">段落文本1<span class="tag"><span></span></p><span class="pln"><br/><span class="tag"><p><span class="pln">段落文本2<span class="tag"><span></span></p><span class="pln"><br/><br/><span class="tag"><script<span class="pln"> <span class="atn">type<span class="pun">=<span class="atv">"text/<a href="http://www.php.cn/wiki/48.html" target="_blank">javascript</a>"<span class="tag">><span class="pln"><br/>$<span class="pun">(<span class="str">"p"<span class="pun">).<span class="pln">wrap<span class="pun">(<span class="pln"> <span class="str">&#39;<p></p>&#39;<span class="pln"> <span class="pun">);<span class="pln"> <br/><span class="tag"></script><span class="pln"><br/><br/><span class="com"><!--以下是jQuery代码执行后的html内容--><span class="pln"><br/><span class="tag"><p><p><span class="pln">段落文本1<span class="tag"><span></span></p></p><span class="pln"><br/><span class="tag"><p><p><span class="pln">段落文本2<span class="tag"><span></span></p></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>

以下面这段HTML代码为例：

<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"><span<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n2"<span class="tag">><span class="pln">span#n2<span class="tag"></span><span class="pln">    <br/><span class="tag"></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 class="pln"><br/>    <span class="tag"><input<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n4"<span class="pln"> <span class="atn">type<span class="pun">=<span class="atv">"text"<span class="pln"> <span class="tag">/><span class="pln"><br/><span class="tag"></p><span class="pln"><br/><span class="tag"><span<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n5"<span class="tag">><span class="pln">多层嵌套1<span class="tag"></span><span class="pln"><br/><span class="tag"><span<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n6"<span class="tag">><span class="pln">多层嵌套2<span class="tag"></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

以下jQuery示例代码用于演示wrap()函数的具体用法：

<span class="com">// 在n2元素外包裹strong元素：<strong>{#n2}</strong><span class="pln"><br/>$<span class="pun">(<span class="str">"#n2"<span class="pun">).<span class="pln">wrap<span class="pun">(<span class="str">&#39;<strong/>&#39;<span class="pun">);<span class="pln"><br/><br/><br/><span class="com">// 在n4元素外包裹form元素：<form name="myForm">{#n4}</form><span class="pln"><br/>$<span class="pun">(<span class="str">"#n4"<span class="pun">).<span class="pln">wrap<span class="pun">(<span class="str">&#39;<form name="myForm"></form>&#39;<span class="pun">);<span class="pln"><br/><br/><br/><span class="com">// 在每个p元素外包裹p元素：<p data_id="index">{p}</p><span class="pln"><br/>$<span class="pun">(<span class="str">"p"<span class="pun">).<span class="pln">wrap<span class="pun">(<span class="pln"> <span class="kwd">function<span class="pun">(<span class="pln">index<span class="pun">){<span class="pln"><br/>    <span class="kwd"><a href="http://www.php.cn/wiki/135.html" target="_blank">return</a><span class="pln"> <span class="str">&#39;<p data_id="&#39;<span class="pln"> <span class="pun">+<span class="pln"> index <span class="pun">+<span class="pln"> <span class="str">&#39;"></p>&#39;<span class="pun">;<span class="pln">   <br/><span class="pun">}<span class="pln"> <span class="pun">);<span class="pln"><br/><br/><br/><span class="com">// 在n5元素外包裹嵌套的p元素：<p><p><em><b>{#n5}</b></em></p></p><span class="pln"><br/>$<span class="pun">(<span class="str">"#n5"<span class="pun">).<span class="pln">wrap<span class="pun">(<span class="pln"> <span class="str">&#39;<p><p><em><b></b></em></p></p>&#39;<span class="pln"> <span class="pun">);<span class="pln"><br/><br/><br/><span class="com">// 在n6元素外包裹嵌套的p元素：<p><p> <em><b></b></em>${#n5}</p></p><span class="pln"><br/><span class="com">// wrap()会从外层p依次往内部查找，以确定n5元素的所在位置<span class="pln"><br/><span class="com">// wrap()将从外往内检查每层嵌套的第一个元素，如果该元素没有子元素或者第一个子元素不是Element节点，就停止向内查找<span class="pln"><br/><span class="com">// 由于参数的&#39;<p>&#39;后面有空格(文本节点)，也就是说p元素的第一个子元素不是Element类型，因此直接将n6插入到p元素内部的末尾位置<span class="pln"><br/>$<span class="pun">(<span class="str">"#n6"<span class="pun">).<span class="pln">wrap<span class="pun">(<span class="pln"> <span class="str">&#39;<p><p> <em><b></b></em></p></p>&#39;<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>

运行代码

wrap()会将包裹元素的开始标记和结束标记分别置于匹配元素的两侧，不会额外添加任何空白字符，上述代码执行后的完整html代码如下(格式未作任何调整)：

<span class="tag"><p<span class="pln"> <span class="atn">data_id<span class="pun">=<span class="atv">"0"<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"><strong><span<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n2"<span class="tag">><span class="pln">span#n2<span class="tag"></span></strong><span class="pln">    <br/><span class="tag"></p></p><span class="pln"><br/><span class="tag"><p<span class="pln"> <span class="atn">data_id<span class="pun">=<span class="atv">"1"<span class="tag">><p<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n3"<span class="tag">><span class="pln"><br/>    <span class="tag"><form<span class="pln"> <span class="atn">name<span class="pun">=<span class="atv">"myForm"<span class="tag">><input<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n4"<span class="pln"> <span class="atn">type<span class="pun">=<span class="atv">"text"<span class="tag">></form><span class="pln"><br/><span class="tag"></p></p><span class="pln"><br/><span class="tag"><p><p><em><b><span<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n5"<span class="tag">><span class="pln">多层嵌套1<span class="tag"></span></b></em></p></p><span class="pln"><br/><span class="tag"><p><p><span class="pln"> <span class="tag"><em><b></b></em><span<span class="pln"> <span class="atn">id<span class="pun">=<span class="atv">"n6"<span class="tag">><span class="pln">多层嵌套2<span class="tag"></span></p></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></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

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