jQuery单击时触发两次

Question

Whe using jQuery .on('click', ...) the function is executed twice:

$(document).ready(function () {
    $('#collapsible-menu li a').click(function() {
        $('#collapsible-menu li').removeClass('active');
        $(this).parent('li').addClass('active');
    });
});

So what happens is that the menu item goes active for an instant and then class goes away.

I have no clue why it's being fired twice. I don't want to use event.preventDefault() or event.preventPropagation() or return false because then clicking the link will lead nowhere.

HTML:

<div class="collapse navbar-collapse" id="collapsible-menu">
  <ul class="nav navbar-nav">
    <li class="active"><a href="/expenses">Expenses</a></li>
    <li class=""><a href="/types">Types</a></li>
  </ul>
</div>

Answer 1

You're clicking an anchor which redirects the page to /types .

When you go to another page, whatever changes the javascript did, is lost.
So you're adding a class, then it redirects and the class is lost, the event handler doesn't fire twice
To avoid redirecting you can prevent the default action of the anchor

$('#collapsible-menu li a').click(function(e) {
    e.preventDefault();
    $('#collapsible-menu li').removeClass('active');
    $(this).parent('li').addClass('active');
});

You can not expect to keep the class, and redirect at the same time, you have to do one or the other.