如果单击已选择的选项，则触发更改事件 [英] Trigger change event if I click on already selected option

问题描述

如果单击已选择的选项，如何触发更改事件.例如，我在下拉列表中有以下选项

How can I trigger change event if I click on already selected option. For example I have following options in dropdown

• 红色
• 蓝色
• 绿色

并且选择了蓝色选项.现在我希望，如果我再次单击蓝色项目，则应该触发更改事件.

and Blue option is selected. Now I want that if I click again on blue item then the change event should fire.

推荐答案

运行 change 即使用户选择了所选选项也是一个已知问题 - 您可以 阅读此处了解它.

Running the change even when the user selects the selected option is a known problem - you can read here about it.

现在，当您知道如何在用户选择任何选项时触发事件时，您只需存储上次使用的值并检查是否选择了相同的项目.

Now, when you know how to trigger an event whenever a user selects any option, you can simply store the last used value and check if the same item is selected.

var previousValue;
$("select")
    .mouseup(function() {
        var open = $(this).data("isopen");

        if (open) {
            if (this.value === previousValue)
            {
                alert("The same select has been clicked");
            }
        }

        previousValue = this.value;
    
        $(this).data("isopen", !open);
    });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<select>
  <option>Red</option>
  <option selected>Green</option>
  <option>Blue</option>
</select>

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