html - 使用 CSS 设置文本区域的 "required"属性样式不起作用

Question

我已使用 required 属性添加了我的输入、姓名、电子邮件等，并通过 CSS 提供了完美表示无效/已验证状态的图标。但是，相同的样式不会在我的表单的两个文本区域中插入图标​​？

我已经看到我应该删除标签之间的所有空格，我确信我已经这样做了，但它没有解决问题。

<form id="from">
  <table width="742" border="0">
    <caption>
    <h1>Your details</h1>
    <br>
    </caption>
  <tr>
    <td width="117">First Name</td>
    <td width="161"><input class="input-small" type="text" placeholder="" required></td>
    <td width="29">&nbsp;</td>
    <td width="242">Date of Birth</td>
    <td width="171"><input class="input-small" type="text" placeholder="eg. 01/05/1975" required></td>
  </tr>
  <tr>
    <td>Surname</td>

    <td><input class="input-small" type="text" placeholder="" required></td>
    <td>&nbsp;</td>
    <td>Phone</td>
    <td><input class="input-small" type="text" placeholder=""></td>
  </tr>
  <tr>
    <td>Address</td>
    <td rowspan="4"><textarea rows="5" class="input-mini" placeholder="Full Postal Address" required></textarea></td>
    <td>&nbsp;</td>
    <td>Email</td>
    <td><input class="input-small" type="email" placeholder="e.g. <a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="84fdebf1c4fdebf1f6aae9e5ede8" rel="noreferrer noopener nofollow">[email protected]</a>" required></td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>Email- Again</td>
    <td><input class="input-small" type="email" placeholder="again" required></td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>Emergency Contact</td>
    <td rowspan="3"><textarea name="emergency" rows="5" placeholder="Emergency" required="required"></textarea>
&nbsp;      &nbsp;</td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
  <tr>
    <td>Postcode</td>
    <td><input class="input-small1" type="text" placeholder="WA1 3DE"></td>
    <td>&nbsp;</td>
    <td>&nbsp;</td>
  </tr>
</table>

<br>
<br>
<br>

<label class="checkbox inline">
  <input type="checkbox" id="inlineCheckbox1" value="option1"> Option
</label>
<label class="checkbox inline">
  <input type="checkbox" id="inlineCheckbox2" value="option2"> Option
</label>
<label class="checkbox inline">
  <input type="checkbox" id="inlineCheckbox3" value="option3"> Option
</label>

</form>

CSS 是:

@charset "utf-8";
#from  {
    position: relative;
    left: 200px;
}
.input-small1 {
    width: 60px;
}
body {
    background-color:#BAFCFA;
}
input:required:invalid, input:focus:invalid {
    background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAeVJREFUeNqkU01oE1EQ/mazSTdRmqSxLVSJVKU9RYoHD8WfHr16kh5EFA8eSy6hXrwUPBSKZ6E9V1CU4tGf0DZWDEQrGkhprRDbCvlpavan3ezu+LLSUnADLZnHwHvzmJlvvpkhZkY7IqFNaTuAfPhhP/8Uo87SGSaDsP27hgYM/lUpy6lHdqsAtM+BPfvqKp3ufYKwcgmWCug6oKmrrG3PoaqngWjdd/922hOBs5C/jJA6x7AiUt8VYVUAVQXXShfIqCYRMZO8/N1N+B8H1sOUwivpSUSVCJ2MAjtVwBAIdv+AQkHQqbOgc+fBvorjyQENDcch16/BtkQdAlC4E6jrYHGgGU18Io3gmhzJuwub6/fQJYNi/YBpCifhbDaAPXFvCBVxXbvfbNGFeN8DkjogWAd8DljV3KRutcEAeHMN/HXZ4p9bhncJHCyhNx52R0Kv/XNuQvYBnM+CP7xddXL5KaJw0TMAF8qjnMvegeK/SLHubhpKDKIrJDlvXoMX3y9xcSMZyBQ+tpyk5hzsa2Ns7LGdfWdbL6fZvHn92d7dgROH/730YBLtiZmEdGPkFnhX4kxmjVe2xgPfCtrRd6GHRtEh9zsL8xVe+pwSzj+OtwvletZZ/wLeKD71L+ZeHHWZ/gowABkp7AwwnEjFAAAAAElFTkSuQmCC);
    background-position: right top;
    background-repeat: no-repeat;
    -moz-box-shadow: none;
}
input:required:valid {
    background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAepJREFUeNrEk79PFEEUx9/uDDd7v/AAQQnEQokmJCRGwc7/QeM/YGVxsZJQYI/EhCChICYmUJigNBSGzobQaI5SaYRw6imne0d2D/bYmZ3dGd+YQKEHYiyc5GUyb3Y+77vfeWNpreFfhvXfAWAAJtbKi7dff1rWK9vPHx3mThP2Iaipk5EzTg8Qmru38H7izmkFHAF4WH1R52654PR0Oamzj2dKxYt/Bbg1OPZuY3d9aU82VGem/5LtnJscLxWzfzRxaWNqWJP0XUadIbSzu5DuvUJpzq7sfYBKsP1GJeLB+PWpt8cCXm4+2+zLXx4guKiLXWA2Nc5ChOuacMEPv20FkT+dIawyenVi5VcAbcigWzXLeNiDRCdwId0LFm5IUMBIBgrp8wOEsFlfeCGm23/zoBZWn9a4C314A1nCoM1OAVccuGyCkPs/P+pIdVIOkG9pIh6YlyqCrwhRKD3GygK9PUBImIQQxRi4b2O+JcCLg8+e8NZiLVEygwCrWpYF0jQJziYU/ho2TUuCPTn8hHcQNuZy1/94sAMOzQHDeqaij7Cd8Dt8CatGhX3iWxgtFW/m29pnUjR7TSQcRCIAVW1FSr6KAVYdi+5Pj8yunviYHq7f72po3Y9dbi7CxzDO1+duzCXH9cEPAQYAhJELY/AqBtwAAAAASUVORK5CYII=);
    background-position: right top;
    background-repeat: no-repeat;
    -moz-box-shadow: none;
}
:invalid {
  box-shadow: none;
}

:-moz-submit-invalid {
  box-shadow: none;
}

:-moz-ui-invalid {
  box-shadow:none;
}

我已将相同的规则应用于文本区域的所有其他输入，但无济于事。

Answer 1

我还没有真正准备好测试这个，但我相当确定这应该可以解决您的问题。它不适用于文本区域的原因是因为您的CSS仅查找输入标签而不是文本区域标签。您应该将其添加到有 input:valid 和 input:invalid

的位置

input:required:invalid, input:focus:invalid, 
textarea:required:invalid, textarea:focus:invalid {
    background-image: url(data:image/png;base64,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);
    background-position: right top;
    background-repeat: no-repeat;
    -moz-box-shadow: none;
}

input:required:valid,
textarea:required:valid {
    background-image: url(data:image/png;base64,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);
    background-position: right top;
    background-repeat: no-repeat;
    -moz-box-shadow: none;
}