javascript JQuery - 从 Selectbox 中删除所有选项，除了 first 和 selected
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JQuery - Remove all option from Selectbox except for first and selected
提问by bos570
I have a html select box with several options. Upon selection of an option I want Only the selected option and the first option to be shown in the select option dropdown. I know how to filter and show only one option but I cannot figure out how to include both option where the 'selected' option remains 'selected'. I have include snippets similar to of my code as well as a demo.
我有一个带有多个选项的 html 选择框。选择一个选项后，我只想在选择选项下拉列表中显示所选选项和第一个选项。我知道如何过滤并只显示一个选项，但我无法弄清楚如何在“选定”选项保持“选定”状态的情况下包含这两个选项。我已经包含了类似于我的代码的片段以及一个演示。
HTML:
HTML：
<select id="myDropdown">
<option selected>Select fruit</option>
<option>Grapes</option>
<option>Bananas</option>
<option>Oranges</option>
<option>Apples</option>
</select>
JS:
JS：
$(document).on('change', '#myDropdown', function() {
$('option', this).not(this,'option:gt(0)').siblings().remove(); });
I am trying to use the first option to perform another function 'on change' so I need the selected option to remain selected while the rest being filtered out except for the first. For example if 'Oranges' were selected, this is what you would see:
我正在尝试使用第一个选项来执行另一个“更改时”功能，因此我需要选择的选项保持选中状态，而其余选项将被过滤掉，但第一个除外。例如，如果选择了“Oranges”，您将看到以下内容：
<select id="myDropdown">
<option>Select fruit</option>
<option>Oranges</option> //selcted value
</select>
BTW I am using jquery mobile to style as well.
顺便说一句，我也在使用 jquery mobile 来设计样式。
回答by Stryner
.notonly takes 1 parameter. If you want to filter on two different selectors, you can add a comma between them inside the string. You can also use the :selectedselector:
.not只需要 1 个参数。如果要过滤两个不同的选择器，可以在字符串内在它们之间添加逗号。您还可以使用:selected选择器：
$('option', this).not(':eq(0), :selected').remove();
See Updated Fiddle: http://jsfiddle.net/znx9hxvu/9/
请参阅更新的小提琴：http: //jsfiddle.net/znx9hxvu/9/
