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jquery checkbox无法用attr()二次勾选问题的解决方法

分类 : 编程语言 | 发布时间 : 2018-04-21 09:06:21 | 浏览 : 0

今晨,漂亮的测试妹妹提了个奇怪的bug,说我一功能checkbox时隐时现,比如第一次打开有勾选,第n次打开可能就不选了。

想到与美女有亲密接触机会,马上鸡动起来。

经过偶层层抽次剥茧(da da jiang you),终于知道了原因:attr()在二次选中勾选框时,失效。

比如,如下HTML页面,一点【选中】、二点【取消选中】、三点【选中】,瞧,不行了呗。

1.html

<!doctype html>
<html lang="en">
<head>
 <meta charset="utf-8">
 <title>prop demo</title>
 <style>
 img {
  padding: 10px;
 }
 div {
  color: red;
  font-size: 24px;
 }
 </style>
 <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
 <input type="checkbox" checked="checked">
 <input type="checkbox">
 <input type="checkbox">
 <input type="checkbox" checked="checked">
 
<script>
$( "input[type='checkbox']" ).prop( "checked", function( i, val ) {
 return !val;
});
</script>
 
</body>
</html>

解决方案,是使用prop()替换attr()方法(在Jquery1.6以上),如下代码:

2.html

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Attr checked</title>
<script type="text/javascript" src="./js/jquery-1.11.2.js"></script>
<script type="text/javascript">
  function switchChecked(flag) {
    $("input[type='checkbox']").prop('checked', flag);
  }
</script>
</head>
<body>
  <input type="checkbox" />
  <input type="button" onclick="switchChecked(true)" value="选中">
  <input type="button" onclick="switchChecked(false)" value="取消选中">
</body>
</html>

关于官方文档,见:http://api.jquery.com/attr/

或者http://api.jquery.com/prop/

摘抄如下:“As of jQuery 1.6, the .attr() method returns undefined for attributes that have not been set. To retrieve and change DOM properties such as the checked, selected, or disabled state of form elements, use the .prop() method.”

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