javascript - 为所有以前的单选按钮和选定的单选按钮添加类

Question

我正在玩一些简单的代码，但无法将其整理出来 :( 我想为选定的单选按钮和之前的单选按钮添加颜色(类)...例如，如果选择了 3 号按钮 1,2,3应该得到一种新颜色。

这是一个简单的代码

<form>
    <ul>
        <li>
            <input id="radio1" type="radio" name="radio[]" value="1">
            <label for="radio1">one</label>
        </li>
        <li>
            <input id="radio2" type="radio" name="radio[]" value="2">
            <label for="radio2">two</label>
        </li>
        <li>
            <input id="radio3" type="radio" name="radio[]" value="3">
            <label for="radio3">three</label>
        </li>
        <li>
            <input id="radio4" type="radio" name="radio[]" value="4">
            <label for="radio4">four</label>
        </li>
        <li>
            <input id="radio5" type="radio" name="radio[]" value="5">
            <label for="radio5">five</label>
        </li>
    </ul>

我试过 .prevAll() 但显然它没有用。

这是为所有按钮添加类的当前脚本

$(document).ready(function(e) { 
    $("input[type=radio]").click(function(){
        $('form ul li input[type=radio] + label').addClass('abc');
    })  
});

演示 https://jsfiddle.net/8jct6tfs/2/

我应该使用循环吗？任何帮助将不胜感激

Answer 1

Use .index() of the closest li element of the clicked element and Using :lt(Elements having smaller index than specified) selector, apply class

试试这个:

$(document).ready(function(e) {
  $("input[type=radio]").click(function() {
    $('form ul li input[type=radio] + label').removeClass('abc')
    var index = $(this).closest('li').index();
    $('form ul li input[type=radio] + label:lt("' + index + '")').addClass('abc');
  })
});

form {
  max-width: 500px;
  margin-top: 25px;
}
form ul li {
  display: inline-block;
  width: 20%;
  text-align: center;
  vertical-align: top;
  float: left;
  position: relative
}
input {
  position: relative;
  top: 0;
  left: 50%;
  margin-left: -6px;
  display: none;
}
input[type=radio]:checked + label::before {
  content: '';
  position: absolute;
  border-radius: 100%;
  left: 50%;
  top: 0;
  width: 30px;
  height: 30px;
  margin: -12px 0 0 -15px;
  background-color: red;
}
input[type=radio] + label::before {
  content: '';
  position: absolute;
  border-radius: 100%;
  left: 50%;
  top: 0;
  width: 30px;
  height: 30px;
  margin: -12px 0 0 -15px;
  background-color: gray;
}
label {
  padding-top: 55px;
}
/*this class should be added*/

input[type=radio] + label.abc::before {
  background-color: red;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<form>
  <ul>
    <li>
      <input id="radio1" type="radio" name="radio[]" value="1">
      <label for="radio1">one</label>
    </li>
    <li>
      <input id="radio2" type="radio" name="radio[]" value="2">
      <label for="radio2">two</label>
    </li>
    <li>
      <input id="radio3" type="radio" name="radio[]" value="3">
      <label for="radio3">three</label>
    </li>
    <li>
      <input id="radio4" type="radio" name="radio[]" value="4">
      <label for="radio4">four</label>
    </li>
    <li>
      <input id="radio5" type="radio" name="radio[]" value="5">
      <label for="radio5">five</label>
    </li>
  </ul>
</form>

Fiddle here