jQuery设置选择索引 [英] jQuery Set Select Index

问题描述

我有一个选择框:

<select id="selectBox">
  <option value="0">Number 0</option>
  <option value="1">Number 1</option>
  <option value="2">Number 2</option>
  <option value="3">Number 3</option>
  <option value="4">Number 4</option>
  <option value="5">Number 5</option>
  <option value="6">Number 6</option>
  <option value="7">Number 7</option>
</select>

我想根据其选定索引将其中一个选项设置为选定".

I'd like to set one of the options as "selected" based on it's selected index.

例如，如果我尝试设置数字3"，则尝试这样做:

For example, if I am trying to set "Number 3", I'm trying this:

$('#selectBox')[3].attr('selected', 'selected');

但这不起作用.如何使用jQuery根据选项的索引将其设置为选中状态?

But this doesn't work. How can I set an option as selected based on it's index using jQuery?

谢谢！

推荐答案

注意:答案取决于jQuery 1.6.1 +

NOTE: answer is dependent upon jQuery 1.6.1+

$('#selectBox :nth-child(4)').prop('selected', true); // To select via index
$('#selectBox option:eq(3)').prop('selected', true);  // To select via value

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感谢您的评论，.get将不起作用，因为它返回的是DOM元素，而不是jQuery元素.请记住，.eq函数也可以在选择器之外使用.

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Thanks for the comment, .get won't work since it returns a DOM element, not a jQuery one. Keep in mind the .eq function can be used outside of the selector as well if you prefer.

$('#selectBox option').eq(3).prop('selected', true);

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如果要使用 value ，也可以更加简洁/可读，而不是依赖于选择特定的 index :

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You can also be more terse/readable if you want to use the value, instead of relying on selecting a specific index:

$("#selectBox").val("3");

注意: .val(3)在此示例中也很好，但是非数字值必须是字符串，因此我选择了一个字符串以保持一致性.
(例如<option value="hello">Number3</option>要求您使用.val("hello"))

Note: .val(3) works as well for this example, but non-numeric values must be strings, so I chose a string for consistency.
(e.g. <option value="hello">Number3</option> requires you to use .val("hello"))

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