使用javascript使用选择（组合框）输入更改段落文本

Question

我正在尝试根据组合框输入将段落中“蓝色”一词的所有实例更改为另一种颜色； 单词的颜色更改为相应的输入。 不知道还有什么可以尝试的。 您可以查看我附加的代码。

 document.querySelector(document).ready(function() { var button = document.querySelector("button_change"); document.querySelector(button).click(function() { var select = document.querySelector("input_color").value; var element = document.querySelector(".cow_color"); document.querySelector(element).html(inputValue); }); });

 <h2> <span class="cow_color">Blue</span> Cow by Gelett Burgess (published in The Lark, 1895) </h2> <p> I never saw a <span class="cow_color">Blue</span> Cow, I never hope to see one; But I can tell you, anyhow, I'd rather see than be one. </p> <p> Change the cow's color to: <select id="input_color"> <option value="Purple">Purple</option> <option value="Green">Green</option> <option value="Red">Red</option> <option value="Yellow">Yellow</option> <option value="Teal">Teal</option> </select> <button id="button_change">Change!</button> </p>

Answer 1

1. 您需要一个 eventListener 或一个 onclick-trigger 来运行脚本。
2. 您使用element.querySelectorAll('.class-name')作为选择器来选择具有该类名的所有类
3. 将更改应用于您使用.forEach(el => el.command)命令的所有元素。

最后的 JS 行应该是：

document.querySelectorAll('.cow_color').forEach(el => elinnerHTML = document.querySelectorAll('#input_color').value;);

 function changeColor() { var inputValue = document.querySelector('#input_color'), cowColor = document.querySelectorAll('.cow_color'); cowColor.forEach(el => el.innerHTML = inputValue.value); }

 <h2> <span class="cow_color">Blue</span> Cow by Gelett Burgess (published in The Lark, 1895) </h2> <p> I never saw a <span class="cow_color">Blue</span> Cow, I never hope to see one; But I can tell you, anyhow, I'd rather see than be one. </p> <p> Change the cow's color to: <select id="input_color"> <option value="Purple">Purple</option> <option value="Green">Green</option> <option value="Red">Red</option> <option value="Yellow">Yellow</option> <option value="Teal">Teal</option> </select> <button id="button_change" onclick="changeColor()">Change!</button> </p>

Answer 2

概述

这是一个 jquery 版本

例子

例子

说明：

我们绑定到按钮，然后在单击事件上，我们从下拉选择中获取值。 使用该值，我们遍历所有.cow_color并使用我们之前获得的值分配颜色，并替换文本。

代码

 $(document).on('click', '#button_change', (element) => { let color = $('#input_color').val(); let spans = $('.cow_color'); spans.map(function() { $(this).css('color', color); $(this).html(color); }); return; });

 <!-- Jquery --> <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script> <!-- Body --> <h2> <span class="cow_color">Blue</span> Cow by Gelett Burgess (published in The Lark, 1895) </h2> <p> I never saw a <span class="cow_color">Blue</span> Cow, I never hope to see one; But I can tell you, anyhow, I'd rather see than be one. </p> <p> Change the cow's color to: <select id="input_color"> <option value="Purple">Purple</option> <option value="Green">Green</option> <option value="Red">Red</option> <option value="Yellow">Yellow</option> <option value="Teal">Teal</option> </select> <button id="button_change">Change!</button> </p>