uTools-Manuals/docs/jQuery/keypress.html

<article class="" id="post-">
<header class="entry-header">
<h1 class="entry-title">.keypress()</h1>
<div class="entry-meta">
						所属分类：<span class="category"><a href="/category/events/">事件</a> &gt; <a href="/category/events/keyboard-events/">键盘事件</a></span>
<span class="pull-right">英文文档：<a href="https://api.jquery123.com/keypress/" target="_blank">.keypress()</a></span>
</div><!-- .entry-meta -->
</header><!-- .entry-header -->
<!-- .entry-header -->
<div class="entry-content">
<article class="entry method" id="keypress1"><h2 class="section-title">
<span class="name">.keypress( handler(eventObject) )</span><span class="returns">返回: <a href="/Types/#jQuery">jQuery</a></span>
</h2>
<div class="entry-wrapper">
<p class="desc"><strong>描述: </strong>为 "keypress" 事件绑定一个处理函数，或者触发元素上的 "keypress" 事件。</p>
<ul class="signatures">
<li class="signature" id="keypress-handlereventObject">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.0/">1.0</a></span>.keypress( handler(eventObject) )</h4>
<ul><li>
<div><strong>handler(eventObject)</strong></div>
<div>类型: <a href="/Types/#Function">Function</a>()</div>
<div>每次事件触发时会执行的函数。</div>
</li></ul>
</li>
<li class="signature" id="keypress-eventData-handlereventObject">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.4.3/">1.4.3</a></span>.keypress(  [eventData ], handler(eventObject) )</h4>
<ul>
<li>
<div><strong>eventData</strong></div>
<div>类型: <a href="/Types/#PlainObject">PlainObject</a>
</div>
<div>一个对象，它包含的数据键值对映射将被传递给事件处理程序。</div>
</li>
<li>
<div><strong>handler(eventObject)</strong></div>
<div>类型: <a href="/Types/#Function">Function</a>()</div>
<div>每次事件触发时会执行的函数。</div>
</li>
</ul>
</li>
<li class="signature" id="keypress">
<h4 class="name">
<span class="version-details">添加的版本: <a href="/category/version/1.0/">1.0</a></span>.keypress()</h4>
<ul><li><div class="null-signature">这个方法不接受任何参数。</div></li></ul>
</li>
</ul>
<div class="longdesc" id="entry-longdesc">
<p><strong>注意:</strong>：由于<code>keypress</code>事件没有统一的官方规范说明，所以在不同的浏览器，不同的浏览器版本，和不同的平台实际使用这个事件时可能遇到的问题。</p>
<p>这个方法的前两个用法是 <code>.bind('keypress', handler)</code> 的快捷方式，第3个不带参数的用法是 <code>.trigger('keypress')</code> 的快捷方式。</p>
<p>当浏览器捕获一个元素上键盘输入时，<code>keypress</code>就会发送个元素。这是类似<code>keydown</code>事件，除了当按键被一直按下（即连续插入字符的场合）时的处理。如果用户按下并按住这个键（不松开释放）的时候，<code>keydown</code>事件只触发一次，但是<code>keypress</code>会在每个字符插入的时候都会触发事件。此外，组合键（如Shift）会触发<code>keydown</code>事件，但不会触发<code>keypress</code>事件。</p>
<p><code>keypress</code>事件处理程序可以附加到任何元素，但该事件只是发送到具有焦点的元素上。不同的浏览器中，可获得焦点的元素略有不同，但是表单元素总是能获取焦点，所以对于此事件类型表单元素是最合适的。</p>
<p>举个例子，看下面的代码</p>
<div class="syntaxhighlighter xml nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">form</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">fieldset</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">input</span> <span class="attribute">id</span>=<span class="value">"target"</span> <span class="attribute">type</span>=<span class="value">"text"</span> <span class="attribute">value</span>=<span class="value">"Hello there"</span> /&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;/<span class="title">fieldset</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">form</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">div</span> <span class="attribute">id</span>=<span class="value">"other"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  Trigger the handler</code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">div</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<p>事件处理函数可以绑定在输入框上：</p>
<div class="syntaxhighlighter javascript nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code>$(<span class="string">"#target"</span>).keypress(<span class="keyword">function</span>() {</code></div></div><div class="container"><div class="line"><code>  alert(<span class="string">"Handler for .keypress() called."</span>);</code></div></div><div class="container"><div class="line"><code>});</code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<p>现在当光标插入点位于表单域并一个键被按下，警告将被显示：</p>
<p>
<span class="output">Handler for .keypress() called.</span>
</p>
<p>如果该键被按下，消息重复。应用不带参数的<code>.keydown()</code>，我们可以手动触发这个事件:</p>
<div class="syntaxhighlighter javascript nogutter">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code>$(<span class="string">'#other'</span>).click(<span class="keyword">function</span>() {</code></div></div><div class="container"><div class="line"><code>  $(<span class="string">"#target"</span>).keypress();</code></div></div><div class="container"><div class="line"><code>});</code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<p>这些代码执行后，点击<span class="output">Trigger the handler</span>同样警报显示。</p>
<p>如果需要任何按键被捕获（例如，要实现网页全局上的快捷键），那么把这个事件附加到<code>document</code>对象上是非常有用的。所有的按键事件都会沿着各自的 DOM 树冒泡到 <code>document</code> 对象上，除非明确停止。</p>
<p>要确定哪个键被按下，我们可以检测传递给处理函数的<a href="/category/events/event-object/">event 对象</a>。而浏览器使用不同的属性来存储这些信息，jQuery的规范了<code>.which</code>属性，以便我们能够可靠地使用它来检索关键代码。</p>
<p>值得注意的是<code>keydown</code> 和 <code>keyup</code>提供一个代码，表示哪一个键被按下，而<code>keypress</code>表示被输入哪个字符。例如，按下了小写的 "a"，在 <code>keydown</code>和<code>keyup</code>  中，对应该键的代码是 65，但是对于 <code>keypress</code> 而言，接收到的代码是 97。如果是大写 "A" 的话，则所有的相关事件接收到的代码都是 65。由于这个区别，若想捕获敲击了哪个特殊键的话，例如，方向键，使用 <code>.keydown()</code>或<code>.keyup()</code> 更好。</p>
</div>
<section class="entry-examples" id="entry-examples"><header><h2 class="underline">例子:</h2></header><div class="entry-example" id="example-0">
<h4><span class="desc">在文本框中按下某个键时，显示 event 对象。注意：输出 event 对象时，要依赖一个简单的 $.print() 插件 (http://api.jquery.com/scripts/events.js)。</span></h4>
<div class="syntaxhighlighter xml ">
<table>
<tbody>
<tr>
<td class="gutter">
<div class="line n1">1</div>
<div class="line n2">2</div>
<div class="line n3">3</div>
<div class="line n4">4</div>
<div class="line n5">5</div>
<div class="line n6">6</div>
<div class="line n7">7</div>
<div class="line n8">8</div>
<div class="line n9">9</div>
<div class="line n10">10</div>
<div class="line n11">11</div>
<div class="line n12">12</div>
<div class="line n13">13</div>
<div class="line n14">14</div>
<div class="line n15">15</div>
<div class="line n16">16</div>
<div class="line n17">17</div>
<div class="line n18">18</div>
<div class="line n19">19</div>
<div class="line n20">20</div>
<div class="line n21">21</div>
<div class="line n22">22</div>
<div class="line n23">23</div>
<div class="line n24">24</div>
<div class="line n25">25</div>
<div class="line n26">26</div>
<div class="line n27">27</div>
<div class="line n28">28</div>
<div class="line n29">29</div>
<div class="line n30">30</div>
<div class="line n31">31</div>
<div class="line n32">32</div>
<div class="line n33">33</div>
<div class="line n34">34</div>
<div class="line n35">35</div>
<div class="line n36">36</div>
<div class="line n37">37</div>
<div class="line n38">38</div>
<div class="line n39">39</div>
<div class="line n40">40</div>
<div class="line n41">41</div>
<div class="line n42">42</div>
<div class="line n43">43</div>
<div class="line n44">44</div>
<div class="line n45">45</div>
<div class="line n46">46</div>
<div class="line n47">47</div>
<div class="line n48">48</div>
<div class="line n49">49</div>
</td>
<td class="code">
<pre><div class="container"><div class="line"><code><span class="doctype">&lt;!DOCTYPE html&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">html</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">style</span>&gt;</span><span class="css"></span></code></div></div><div class="container"><div class="line"><code><span class="tag">fieldset</span> <span class="rules">{ <span class="rule"><span class="attribute">margin-bottom</span>:<span class="value"> <span class="number">1</span>em;</span></span> <span class="rule">}</span></span></code></div></div><div class="container"><div class="line"><code><span class="tag">input</span> <span class="rules">{ <span class="rule"><span class="attribute">display</span>:<span class="value"> block;</span></span> <span class="rule"><span class="attribute">margin-bottom</span>:<span class="value"> .<span class="number">25</span>em;</span></span> <span class="rule">}</span></span></code></div></div><div class="container"><div class="line"><code><span class="id">#print-output</span> <span class="rules">{</span></code></div></div><div class="container"><div class="line"><code>  <span class="rule"><span class="attribute">width</span>:<span class="value"> <span class="number">100</span>%;</span></span></code></div></div><div class="container"><div class="line"><code><span class="rule">}</span></code></div></div><div class="container"><div class="line"><code><span class="class">.print-output-line</span> <span class="rules">{</span></code></div></div><div class="container"><div class="line"><code>  <span class="rule"><span class="attribute">white-space</span>:<span class="value"> pre;</span></span></code></div></div><div class="container"><div class="line"><code>  <span class="rule"><span class="attribute">padding</span>:<span class="value"> <span class="number">5</span>px;</span></span></code></div></div><div class="container"><div class="line"><code>  <span class="rule"><span class="attribute">font-family</span>:<span class="value"> monaco, monospace;</span></span></code></div></div><div class="container"><div class="line"><code>  <span class="rule"><span class="attribute">font-size</span>:<span class="value"> .<span class="number">7</span>em;</span></span></code></div></div><div class="container"><div class="line"><code><span class="rule">}</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">style</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">script</span> <span class="attribute">src</span>=<span class="value">"https://code.jquery.com/jquery-latest.js"</span>&gt;</span><span class="javascript"></span><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">head</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">form</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;<span class="title">fieldset</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">label</span> <span class="attribute">for</span>=<span class="value">"target"</span>&gt;</span>Type Something:<span class="tag">&lt;/<span class="title">label</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>    <span class="tag">&lt;<span class="title">input</span> <span class="attribute">id</span>=<span class="value">"target"</span> <span class="attribute">type</span>=<span class="value">"text"</span> /&gt;</span></code></div></div><div class="container"><div class="line"><code>  <span class="tag">&lt;/<span class="title">fieldset</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">form</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">button</span> <span class="attribute">id</span>=<span class="value">"other"</span>&gt;</span></code></div></div><div class="container"><div class="line"><code>  Trigger the handler</code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">button</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">script</span> <span class="attribute">src</span>=<span class="value">"http://api.jquery.com/resources/events.js"</span>&gt;</span><span class="javascript"></span><span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;<span class="title">script</span>&gt;</span><span class="javascript"></span></code></div></div><div class="container"><div class="line"><code><span class="keyword">var</span> xTriggered = <span class="number">0</span>;</code></div></div><div class="container"><div class="line"><code>$(<span class="string">"#target"</span>).keypress(<span class="keyword">function</span>(event) {</code></div></div><div class="container"><div class="line"><code>  <span class="keyword">if</span> ( event.which == <span class="number">13</span> ) {</code></div></div><div class="container"><div class="line"><code>     event.preventDefault();</code></div></div><div class="container"><div class="line"><code>   }</code></div></div><div class="container"><div class="line"><code>   xTriggered++;</code></div></div><div class="container"><div class="line"><code>   <span class="keyword">var</span> msg = <span class="string">"Handler for .keypress() called "</span> + xTriggered + <span class="string">" time(s)."</span>;</code></div></div><div class="container"><div class="line"><code>  $.print( msg, <span class="string">"html"</span> );</code></div></div><div class="container"><div class="line"><code>  $.print( event );</code></div></div><div class="container"><div class="line"><code>});</code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code>$(<span class="string">"#other"</span>).click(<span class="keyword">function</span>() {</code></div></div><div class="container"><div class="line"><code>  $(<span class="string">"#target"</span>).keypress();</code></div></div><div class="container"><div class="line"><code>});<span class="tag">&lt;/<span class="title">script</span>&gt;</span></code></div></div><div class="container"><div class="line"><code> </code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">body</span>&gt;</span></code></div></div><div class="container"><div class="line"><code><span class="tag">&lt;/<span class="title">html</span>&gt;</span></code></div></div></pre>
</td>
</tr>
</tbody>
</table>
</div>
<h4>Demo:</h4>
<div class="demo code-demo" data-height="460"></div>
</div></section>
</div></article> </div>
</article>