Javascript 在 jQuery 中显示选择下拉列表？
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Show select dropdown in jQuery?
提问by Hailwood
Possible Duplicate:
How can you programmatically tell an HTML SELECT to drop down (for example, due to mouseover)?
Is it possible to make the dropdown on a select element visible with jQuery?
是否可以使用jQuery使选择元素上的下拉列表可见？
I tried using $('#dropdown').click();, but it has no effect.
我尝试使用$('#dropdown').click();，但没有效果。
回答by Stuck
This is not possible. You can only implement your own select-box, but this is bad for usability.
这不可能。您只能实现自己的选择框，但这不利于可用性。
another approach is to programmatically change the size-attribute of the select-box, but this is not really what you wanted.
另一种方法是以编程方式更改选择框的大小属性，但这并不是您真正想要的。
I suggest to think of why you need this and if there would be a nicer software-pattern?
我建议想想你为什么需要这个，以及是否会有更好的软件模式？
回答by Jonathon Bolster
No - you are unable to do this. It's roughly along the same lines of a button in it's pressed state when a user clicks it - an 'interim' operation for the user to set a value. You could focusto it, but that's about it.
不 - 你不能这样做。当用户单击按钮时，它与处于按下状态的按钮大致相同——这是用户设置值的“临时”操作。你可以focus，但仅此而已。
If you reallywanted to simulate this, you could play with some CSS. For example, you could create a list that lookslike the dropdown list and set the dropdown value based on whatever the user clicks - similar to how an autocomplete list looks.
如果你真的想模拟这个，你可以玩一些 CSS。例如，您可以创建一个看起来像下拉列表的列表，并根据用户单击的内容设置下拉值 - 类似于自动完成列表的外观。
You could always change it to a multiple line list box if you wanted to display all the values to the user. You'd do this by setting the sizeto any value and back to 1 when you want to hide. It's not perfect, but it's another option:
如果您想向用户显示所有值，您始终可以将其更改为多行列表框。您可以通过将 设置size为任何值并在想要隐藏时返回 1 来实现。它并不完美，但它是另一种选择：
$("#open").click(function(e){
e.preventDefault();
$("#myselect").attr("size",5);
});
$("#myselect").click(function(){
$(this).attr("size",1);
});
回答by sje397
Here's my adaption:
这是我的改编：
HTML
HTML
<button id='btn'>Click Me</button>
<select id='test'>
<option>Blah 1</option>
<option>Blah 2</option>
<option>Blah 3</option>
<option>Blah 4</option>
</select>
JavaScript
JavaScript
$('#btn').click(function(){
$('#test').attr('size', 5);
});
$('#test').change(function() {
$(this).attr('size', 1);
});
This doesn't open the drop list, but it kind of works.
这不会打开下拉列表，但它有点工作。
Demo here.
演示在这里。
