JavaScript 中的 change

JavaScript 中的 change

什么是 change 事件？

change 事件是 HTML 表单元素的一种事件类型，当表单元素的值发生变化并且失去焦点时，该事件会被触发。常见的表单元素包括、</code>。</p> <h4><a name="t1"></a>适用元素</h4> <ul><li><code><input></code>（type 为 text、checkbox、radio 等）</li><li><code><select></code></li><li><code><textarea></code></li></ul> <p>基本使用</p> <pre data-index="0" class="set-code-hide" name="code"><code class="language-html hljs language-xml"><ol class="hljs-ln" style="width:100%"><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="1"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-meta"><!DOCTYPE <span class="hljs-keyword">html</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="2"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-tag"><<span class="hljs-name">html</span> <span class="hljs-attr">lang</span>=<span class="hljs-string">"en"</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="3"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-tag"><<span class="hljs-name">head</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="4"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">meta</span> <span class="hljs-attr">charset</span>=<span class="hljs-string">"UTF-8"</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="5"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">meta</span> <span class="hljs-attr">name</span>=<span class="hljs-string">"viewport"</span> <span class="hljs-attr">content</span>=<span class="hljs-string">"width=device-width, initial-scale=1.0"</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="6"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">title</span>></span>Change Event Demo<span class="hljs-tag"></<span class="hljs-name">title</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="7"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-tag"></<span class="hljs-name">head</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="8"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-tag"><<span class="hljs-name">body</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="9"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">form</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"myForm"</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="10"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">label</span> <span class="hljs-attr">for</span>=<span class="hljs-string">"myInput"</span>></span>Input:<span class="hljs-tag"></<span class="hljs-name">label</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="11"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">input</span> <span class="hljs-attr">type</span>=<span class="hljs-string">"text"</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"myInput"</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="12"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="13"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">label</span> <span class="hljs-attr">for</span>=<span class="hljs-string">"mySelect"</span>></span>Select:<span class="hljs-tag"></<span class="hljs-name">label</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="14"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">select</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"mySelect"</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="15"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">option</span> <span class="hljs-attr">value</span>=<span class="hljs-string">"1"</span>></span>Option 1<span class="hljs-tag"></<span class="hljs-name">option</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="16"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">option</span> <span class="hljs-attr">value</span>=<span class="hljs-string">"2"</span>></span>Option 2<span class="hljs-tag"></<span class="hljs-name">option</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="17"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">option</span> <span class="hljs-attr">value</span>=<span class="hljs-string">"3"</span>></span>Option 3<span class="hljs-tag"></<span class="hljs-name">option</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="18"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"></<span class="hljs-name">select</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="19"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="20"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">label</span> <span class="hljs-attr">for</span>=<span class="hljs-string">"myTextarea"</span>></span>Textarea:<span class="hljs-tag"></<span class="hljs-name">label</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="21"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">textarea</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"myTextarea"</span>></span><span class="hljs-tag"></<span class="hljs-name">textarea</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="22"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="23"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">button</span> <span class="hljs-attr">type</span>=<span class="hljs-string">"submit"</span>></span>Submit<span class="hljs-tag"></<span class="hljs-name">button</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="24"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"></<span class="hljs-name">form</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="25"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="26"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-tag"><<span class="hljs-name">script</span> <span class="hljs-attr">src</span>=<span class="hljs-string">"app.js"</span>></span><span class="hljs-tag"></<span class="hljs-name">script</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="27"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-tag"></<span class="hljs-name">body</span>></span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="28"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-tag"></<span class="hljs-name">html</span>></span></div></div></li></ol></code><div class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}" onclick="hljs.signin(event)"></div></pre> <p> js</p> <pre data-index="1" class="set-code-hide" name="code"><code class="language-javascript hljs"><ol class="hljs-ln" style="width:100%"><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="1"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-variable language_">document</span>.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'DOMContentLoaded'</span>, <span class="hljs-function">() =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="2"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> inputElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'myInput'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="3"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> selectElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'mySelect'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="4"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> textareaElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'myTextarea'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="5"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="6"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> inputElement.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'change'</span>, <span class="hljs-function">(<span class="hljs-params">event</span>) =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="7"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'Input changed to:'</span>, event.<span class="hljs-property">target</span>.<span class="hljs-property">value</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="8"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> });</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="9"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="10"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> selectElement.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'change'</span>, <span class="hljs-function">(<span class="hljs-params">event</span>) =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="11"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'Select changed to:'</span>, event.<span class="hljs-property">target</span>.<span class="hljs-property">value</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="12"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> });</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="13"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="14"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> textareaElement.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'change'</span>, <span class="hljs-function">(<span class="hljs-params">event</span>) =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="15"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-variable language_">console</span>.<span class="hljs-title function_">log</span>(<span class="hljs-string">'Textarea changed to:'</span>, event.<span class="hljs-property">target</span>.<span class="hljs-property">value</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="16"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> });</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="17"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line">});</div></div></li></ol></code><div class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}" onclick="hljs.signin(event)"></div></pre> <p>在上面的代码中，我们为每个表单元素添加了一个 <code>change</code> 事件监听器。当用户改变元素的值并且<a href="https://so.csdn.net/so/search?q=%E5%A4%B1%E5%8E%BB%E7%84%A6%E7%82%B9&spm=1001.2101.3001.7020" target="_blank" class="hl hl-1" data-report-view="{"spm":"1001.2101.3001.7020","dest":"https://so.csdn.net/so/search?q=%E5%A4%B1%E5%8E%BB%E7%84%A6%E7%82%B9&spm=1001.2101.3001.7020","extra":"{\"searchword\":\"失去焦点\"}"}" data-report-click="{"spm":"1001.2101.3001.7020","dest":"https://so.csdn.net/so/search?q=%E5%A4%B1%E5%8E%BB%E7%84%A6%E7%82%B9&spm=1001.2101.3001.7020","extra":"{\"searchword\":\"失去焦点\"}"}" data-tit="失去焦点" data-pretit="失去焦点">失去焦点</a>时，事件会被触发，控制台会输出相应的信息。</p> <h3><a name="t2"></a><code>change</code> 事件的实际应用</h3> <h4><a name="t3"></a>实时表单验证</h4> <p><code>change</code> 事件常用于实时表单验证。例如，我们可以在用户输入内容后，立即验证输入的有效性并给予反馈：</p> <pre data-index="2" class="set-code-show" name="code"><code class="language-javascript hljs"><ol class="hljs-ln" style="width:736px"><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="1"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-variable language_">document</span>.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'DOMContentLoaded'</span>, <span class="hljs-function">() =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="2"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> inputElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'myInput'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="3"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="4"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> inputElement.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'change'</span>, <span class="hljs-function">(<span class="hljs-params">event</span>) =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="5"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> value = event.<span class="hljs-property">target</span>.<span class="hljs-property">value</span>;</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="6"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> feedbackElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'feedback'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="7"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="8"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">if</span> (value.<span class="hljs-property">length</span> < <span class="hljs-number">3</span>) {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="9"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> feedbackElement.<span class="hljs-property">textContent</span> = <span class="hljs-string">'Input must be at least 3 characters long.'</span>;</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="10"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> } <span class="hljs-keyword">else</span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="11"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> feedbackElement.<span class="hljs-property">textContent</span> = <span class="hljs-string">''</span>;</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="12"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> }</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="13"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> });</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="14"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line">});</div></div></li></ol></code><div class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}" onclick="hljs.signin(event)"></div></pre> <h4><a name="t4"></a>动态更新界面</h4> <p><code>change</code> 事件也可以用于根据用户选择动态更新界面内容。例如，当用户选择一个选项时，显示对应的详细信息：</p> <pre data-index="3" class="set-code-show" name="code"><code class="language-javascript hljs"><ol class="hljs-ln" style="width:100%"><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="1"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"><span class="hljs-variable language_">document</span>.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'DOMContentLoaded'</span>, <span class="hljs-function">() =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="2"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> selectElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'mySelect'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="3"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> detailsElement = <span class="hljs-variable language_">document</span>.<span class="hljs-title function_">getElementById</span>(<span class="hljs-string">'details'</span>);</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="4"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="5"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> details = {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="6"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-string">'1'</span>: <span class="hljs-string">'Details for Option 1'</span>,</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="7"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-string">'2'</span>: <span class="hljs-string">'Details for Option 2'</span>,</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="8"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-string">'3'</span>: <span class="hljs-string">'Details for Option 3'</span></div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="9"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> };</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="10"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> </div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="11"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> selectElement.<span class="hljs-title function_">addEventListener</span>(<span class="hljs-string">'change'</span>, <span class="hljs-function">(<span class="hljs-params">event</span>) =></span> {</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="12"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> <span class="hljs-keyword">const</span> value = event.<span class="hljs-property">target</span>.<span class="hljs-property">value</span>;</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="13"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> detailsElement.<span class="hljs-property">textContent</span> = details[value] || <span class="hljs-string">'No details available'</span>;</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="14"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line"> });</div></div></li><li><div class="hljs-ln-numbers"><div class="hljs-ln-line hljs-ln-n" data-line-number="15"></div></div><div class="hljs-ln-code"><div class="hljs-ln-line">});</div></div></li></ol></code><div class="hljs-button signin active" data-title="登录复制" data-report-click="{"spm":"1001.2101.3001.4334"}" onclick="hljs.signin(event)"></div></pre> <h3><a name="t5"></a>注意事项</h3> <ol><li> <p><strong><code>change</code> 与 <code>input</code> 事件的区别</strong>：</p> <ul><li><code>change</code> 事件在元素失去焦点时触发，而 <code>input</code> 事件在元素的值每次发生变化时立即触发。</li><li><code>input</code> 事件适用于需要实时更新的场景，例如搜索框的自动补全。</li></ul></li><li> <p><strong>跨浏览器兼容性</strong>：</p> <ul><li><code>change</code> 事件在主流浏览器中均有良好的支持，但在某些旧版浏览器中可能存在细微差异。因此，建议在实际项目中进行充分的测试。</li></ul></li></ol> <p><code>change</code> 事件是一个非常有用的事件类型，特别适用于表单元素的值变化检测和处理。在实际开发中，合理使用 <code>change</code> 事件可以提升用户体验，提高表单交互的动态性和响应性。希望本文对你理解和使用 <code>change</code> 事件有所帮助。 </p> </div> </div> </li> <li class="list-group-item ul-li"> <b>相关阅读:</b><br> <nobr> <a href="/Article/Index/1417014">甲骨文真的要开放Java EE？</a> <br /> <a 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什么是 change 事件？

什么是 `change` 事件？