如何使用jQuery选择/取消选择选择列表中的所有选项? [英] How does one select/unselect all options in a select List using jQuery?

问题描述

我还不熟悉jQuery，因此很难获得正确的语法. 我试图根据是否选中复选框来一次选择或取消选择一个selectlist元素的所有元素.

I am not yet familiar with jQuery, so it's been difficult to get the syntax correct for this. I'm trying to select or unselect all the elements of a selectlist element, all at once, based on whether a checkbox is checked or not.

我在SO上找到了一些帮助，但是经过大量的查找和测试之后，需要询问社区...

I found some help here at SO, but after a lot of looking and testing, need to ask the community...

在下面的if/else分支中，else分支正常工作:

In the if/else branch below, the else branch works correctly:

   if ($('input[name="select_markers"]:checked').length > 0) {
        $("#markerlist").prop('selected',true);
    } else {
        $('form select option').prop('selected',false);
    }

但是，这会影响表单中所有不希望的选择元素.我只想影响元素#markerlist，这是我尝试在if分支中执行的操作-但我无法使这一部分正常工作.

However, this affects all the select elements in the form, which I don't want. I only want to affect the element #markerlist, which I am attempting to do in the if branch -- but I cannot get this part to work.

我已经看到了许多其他遍历select元素的示例，但是如果可以的话，我想使这种更简洁的语法起作用.

I've seen many other examples that iterate over a select element, but I'd like to get this cleaner syntax to work, if I can.

TIA， rixter

TIA, rixter

推荐答案

我建议:

$('input[name="select_markers"]').change(
    function(){
        if ($(this).is(':checked')){
            $('#markerlist').find('option').prop('selected','selected')
        }
        else {
            $('#markerlist').find('option').prop('selected',false)
        }
    });

JS Fiddle演示.

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