使用jQuery在“名称”属性中带有“ []”括号时，如何预选单选按钮？

Question

If I remove the [ and ] in the name attribute this script works. What am I doing wrong? I want to post array to the backend so I'm using array syntax in the HTML.

HTML:

<input type="radio" name="a[1]" id="1" value="0"/>
<label for="1">option1</label>

<input type="radio" name="a[1]" id="2" value="1"/>
<label for="2">option2</label>

<input type="radio" name="a[1]" id="3" value="2"/>
<label for="3">option3</label>

<input type="radio" name="a[1]" id="4" value="3"/>
<label for="4">option4</label>

JavaScript:

<script>
    $(document).ready(function() {
        $("input[name=a[1]][value=" + 2 + "]").prop('checked', true);
    });
</script>

Answer 1

Put attribute value (ie a[1] in your case) in single quotes as shown below :

 <script>
    $(document).ready(function() {
        $("input[name='a[1]'][value=" + 2 + "]").prop('checked', true);
    });
 </script>

From the docs for attribute-equals-selector ...

attribute An attribute name.

value An attribute value. Can be either an unquoted single word or a quoted string.

Since you have more than just a single word, it should be quoted.

Fiddle Demo