Javascript 将焦点设置在特定的选择框上
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Set focus on specific select box
提问by α?jiβ
I have multiple select boxes in the pages. I want to set focus on first element of specific select box. Hereit shows how to set focus on select box. I need to say which one too. I tried below code but it didn't set the focus.
我在页面中有多个选择框。我想将焦点设置在特定选择框的第一个元素上。这里展示了如何在选择框上设置焦点。我也得说是哪一个。我尝试了下面的代码，但它没有设置焦点。
$('#thirdDropBox select:first').focus();
回答by Will
If you want the user to have focus on the first of multiple select's, you can use the following jQuery code:
如果您希望用户专注于多个选择中的第一个，您可以使用以下 jQuery 代码：
If you have an id for the first select, you can directly access that element with the following:
如果您有第一个选择的 id，则可以使用以下命令直接访问该元素：
$(document).ready(function () {
$('#idOfFirstSelect').focus();
});
However, if you don't have the id, the following code should work.
但是，如果您没有 id，则以下代码应该可以工作。
Demo: http://jsfiddle.net/biz79/1qo6mxnf/
演示：http: //jsfiddle.net/biz79/1qo6mxnf/
$(document).ready(function () {
$('select').first().focus();
});
On a separate note, if you also want to have a default option selected, you can set that option to "selected" in the HTML:
另外，如果您还想选择一个默认选项，您可以在 HTML 中将该选项设置为“已选择”：
<option value="saab" selected="selected">Saab</option>
回答by PvdBlankevoort
The JQuery selector:
JQuery 选择器：
$('#thirdDropBox select:first')
will select the first "select" html element that is a descendant of an html-element that has an ID-attribute with the value "thirdDropBox".
将选择第一个“选择”html 元素，该元素是具有值为“thirdDropBox”的 ID 属性的 html 元素的后代。
For more information see: http://api.jquery.com/descendant-selector/
有关更多信息，请参阅：http: //api.jquery.com/descendant-selector/
You probably need to remove the '#thirdDropBox"-part from your selector:
您可能需要从选择器中删除“#thirdDropBox”部分：
$('select:first')
