如果选中“其他”复选框，如何使文本框需要填写？我不介意只在选中复选框或不选中复选框时才出现文本框。否则，如果未选中“其他”复选框，则不要求文本框中有输入。

注意：不能使用jQuery或内联JavaScript。必须链接到外部JavaScript文件。

顺晟科技：

您可以做的是侦听所需复选框（这里我们取另一个）的值的变化，这样当复选框的值（选中或不选中）发生变化时，我们可以使用js将required属性设置为true for textarea（这里是另一个框），以此类推..

解决方案

HTML

        
       <form>
        <label>Skills</label>
        <br>
        <br>
        <input type="checkbox" id="skill1" name="skill1" value="Javascript">
        <label for="skill1"> Extensive knowledge of Javascript</label>
        <br>
        <br>
        <input type="checkbox" id="skill2" name="skill2" value="Python">
        <label for="skill2"> Extensive knowledge of Python</label>
        <br>
        <br>
        <input type="checkbox" id="skill3" name="skill3" value="C#">
        <label for="skill3"> Extensive knowledge of Networking</label>
        <br>
        <br>
        <input type="checkbox" id="skill4" name="skill4" value="C#">
        <label for="skill4"> Extensive knowledge of Data storage fundamentals</label>
        <br>
        <br>
        <input type="checkbox" id="skill5" name="skill5" value="C#">
        <label for="skill5"> Extensive knowledge of Security foundations</label>
        <br>
        <br>
        <input type="checkbox" id="skill6" name="skill6" value="C#">
        <label for="skill6"> Extensive knowledge of AWS service selection</label>
        <br>
        <br>
        <input type="checkbox" id="skill7" name="skill7" value="C#">
        <label for="skill7"> Ability to work in a team</label>
        <br>
        <br>
        <input type="checkbox" id="skill8" name="skill8" value="C#">
        <label for="skill8"> 5+ years experience</label>
        <br>
        <br>
        <input type="checkbox" id="skill9" name="skill9" value="C#">
        <label for="skill9"> 10+ years experience</label>
        <br>
        <br>
        <input type="checkbox" id="skill10" name="skill10" value="C#">
        <label for="skill10"> 20+ years experience</label>
        <br>
        <br>
        <input type="checkbox" id="other" name="other" value="other">
        <label for="other"> I have other skills. Please list other skills below.</label>
        <br>
        <br>
        <br>
        <label for="subject">Subject:</label>
        <textarea id="otherbox" name="subject" placeholder="textarea" style="height:200px"></textarea>
        <input type="submit" value="Apply">
      </form>

JS

        
       <form>
        <label>Skills</label>
        <br>
        <br>
        <input type="checkbox" id="skill1" name="skill1" value="Javascript">
        <label for="skill1"> Extensive knowledge of Javascript</label>
        <br>
        <br>
        <input type="checkbox" id="skill2" name="skill2" value="Python">
        <label for="skill2"> Extensive knowledge of Python</label>
        <br>
        <br>
        <input type="checkbox" id="skill3" name="skill3" value="C#">
        <label for="skill3"> Extensive knowledge of Networking</label>
        <br>
        <br>
        <input type="checkbox" id="skill4" name="skill4" value="C#">
        <label for="skill4"> Extensive knowledge of Data storage fundamentals</label>
        <br>
        <br>
        <input type="checkbox" id="skill5" name="skill5" value="C#">
        <label for="skill5"> Extensive knowledge of Security foundations</label>
        <br>
        <br>
        <input type="checkbox" id="skill6" name="skill6" value="C#">
        <label for="skill6"> Extensive knowledge of AWS service selection</label>
        <br>
        <br>
        <input type="checkbox" id="skill7" name="skill7" value="C#">
        <label for="skill7"> Ability to work in a team</label>
        <br>
        <br>
        <input type="checkbox" id="skill8" name="skill8" value="C#">
        <label for="skill8"> 5+ years experience</label>
        <br>
        <br>
        <input type="checkbox" id="skill9" name="skill9" value="C#">
        <label for="skill9"> 10+ years experience</label>
        <br>
        <br>
        <input type="checkbox" id="skill10" name="skill10" value="C#">
        <label for="skill10"> 20+ years experience</label>
        <br>
        <br>
        <input type="checkbox" id="other" name="other" value="other">
        <label for="other"> I have other skills. Please list other skills below.</label>
        <br>
        <br>
        <br>
        <label for="subject">Subject:</label>
        <textarea id="otherbox" name="subject" placeholder="textarea" style="height:200px"></textarea>
        <input type="submit" value="Apply">
      </form>