Moving up multiple parents in jQuery - more effici

2019-02-12 03:35发布

So, I have a navigation that is a list and has sublists and sublists.

Basically, the nav is by default collapsed, but if people click on a page that's in a sublist, I want to show the parent list. And if it's a sublist of a sublist, I need both parent lists to show. I have it set up, but, I don't like putting 5 .parent().parent() 's to traverse upward to expand the list. Is there a more efficient way?

the HTML:

<div id="lesson-sidebar">
        <ul>
            <li><a href="index.html">Welcome to Beat Basics and Beyond</a></li>
            <li><a href="table-of-contents.html">What's in this course?</a></li>
            <li><a href="defining-your-beat.html" class="active">Defining Your Beat</a>
                <ul>
                    <li><a href="boundaries-of-your-beat.html">Boundaries of Your Beat</a></li>
                    <li><a href="the-beat-description.html">The Beat Description</a></li>
                    <li><a href="build-your-own-beat-description.html"><span class="ital">Activity:</span> Build Your Own Beat Description</a></li>
                </ul>
            </li>
            <li><a href="getting-started.html">Getting Started</a>
                <ul>
                    <li><a href="debrief-your-predecessor.html">Debrief Your Predecessor</a></li>
                    <li><a href="predecessor-top-five-tips.html"><span class="ital">Activity:</span> List The Top Five Tips From Your Predecessor</a></li>
                    <li><a href="covering-your-beat-with-the-internet.html">Covering Your Beat With The Internet</a></li>
                    <li><a href="get-in-the-car-and-go.html">Get in the Car and Go</a></li>
                    <li><a href="mapping-your-beat.html">Mapping Your Beat</a></li>
                    <li><a href="read-the-clips.html">Read the Clips</a></li>
                    <li><a href="activity-dissect-this-clip.html"><span class="ital">Activity:</span> Dissect This Clip</a></li>
                    <li><a href="writing-your-first-article.html">Writing Your First Article</a></li>
                    <li><a href="starting-cold-on-the-beat.html">Starting Cold on the Beat</a></li>
                </ul>           
            </li>
            <li><a href="working-with-sources.html">Working With Sources</a>
                <ul>
                    <li><a href="finding-sources.html">Finding Sources</a></li>
                    <li><a href="diversify-your-sources.html">Diversify Your Sources</a></li>
                    <li><a href="prospecting-for-stories-and-sources.html">Prospecting for Stories and Sources</a></li>
                    <li><a href="building-relationships.html">Building Relationships</a></li>
                    <li><a href="going-off-the-record.html">Going Off the Record</a></li>
                </ul>
            </li>
            <li><a href="developing-resources.html">Developing Resources to Help You on the Beat</a>
                <ul>
                    <li><a href="develop-a-calendar-of-events.html">Develop a Calendar of Events</a></li>
                    <li><a href="build-your-library.html">Build Your Library</a></li>
                    <li><a href="learn-the-open-record-laws.html">Learn the Open Record Laws</a></li>
                </ul>
            </li>
            <li><a href="extra-resources.html">Extra Resources</a>
                <ul>
                    <li><a href="beat-breakdown-tool.html">Beat Breakdown Tool</a></li>
                    <li><a href="links-library.html">Links Library</a>
                        <ul>
                            <li><a href="general-resources-for-any-beat.html">General Resources for Any Beat</a></li>
                            <li><a href="courts-and-criminal-justice-links.html">Courts and Criminal Justice Links</a></li>
                            <li><a href="education-resources.html">Education Resources</a></li>
                            <li><a href="local-government-links.html">Local Government Links</a></li>
                            <li><a href="neighborhood-or-suburban-links.html">Neighborhood or Suburban Links</a></li>
                            <li><a href="police-and-public-safety-links.html">Police and Public Safety Links</a></li>
                            <li><a href="reporter-organizations.html">Reporter Organizations</a></li>
                        </ul>
                    </li>
                    <li><a href="additional-reading.html">Additional Reading</a></li>
                </ul>
            </li>
            <li><a href="final-thoughts.html">Final Thoughts</a></li>
        </ul>

The jQuery:

function toggleSubmenu() {

    if ($(this).hasClass('submenu-hidden')) {

        $(this).parent().children('ul').slideToggle();
        $(this).removeClass().addClass('submenu-visible');

    } else if ($(this).hasClass('submenu-visible')) {

        $(this).parent().children('ul').slideToggle();
        $(this).removeClass().addClass('submenu-hidden');
    }
}

$('#lesson-sidebar ul ul').hide();
$('#lesson-sidebar ul ul ul').hide();
$('#lesson-sidebar ul:first-child').attr('id', 'rootlist');
$('#lesson-sidebar ul li:has("ul")').prepend('<span class="submenu-hidden"></span>').css('list-style','none');

$('#lesson-sidebar ul li a').each(
    function() {
        if ($(this).hasClass('active')) {
            // if it is a UL
            var length = $(this).parent().find("ul").length;
            alert(length);
            if (length == 0) {
                if ($(this).parent().parent().parent().children('span').hasClass('submenu-hidden')) {
                        $(this).parent().parent().parent().children('ul').show();
                        $(this).parent().parent().parent().children('span').removeClass('submenu-hidden').addClass('submenu-visible');
                }
                if ($(this).parent().parent().parent().parent().parent().children('span').hasClass('submenu-hidden')) {
                        $(this).parent().parent().parent().parent().parent().children('ul').show();
                        $(this).parent().parent().parent().parent().parent().children('span').removeClass('submenu-hidden').addClass('submenu-visible');
                } 
            }
            if (length == 1) {
                $(this).parent().find('ul').slideToggle();
                $(this).parent().children('span').removeClass('submenu-hidden').addClass('submenu-visible');
            }               
        }
    }
);

$('ul#rootlist > li span, ul#rootlist li ul li > span').bind('click', toggleSubmenu);

Any and all help is majorly appreciated.

5条回答
Ridiculous、
2楼-- · 2019-02-12 03:49

If I understand what you're trying to do... you can do something like this:

// For my benefit, hide all lists except the root items
$('ul, li', $('#lesson-sidebar ul li')).hide();

// Show active parents and their siblings
$('li a.active').parents('ul, li').each(function() {
    $(this).siblings().andSelf().show();
});

// Show the active item and its siblings
$('li a.active').siblings().andSelf().show();

The parents() and siblings() methods are both great for this kind of thing.

Edit: There was a bug before where it wasn't showing parent siblings. Try this new version.

Edit 2: Now it works with class="active" on the anchor instead of the list item.

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smile是对你的礼貌
3楼-- · 2019-02-12 03:52

Try with this code line:

$(this).parent().parent().fadeOut();
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干净又极端
4楼-- · 2019-02-12 03:53

To simplify Lance McNeary's very helpful answer, the trick is to use:

.parents([selector])

Given a jQuery object that represents a set of DOM elements, the .parents() method allows us to search through the ancestors of these elements in the DOM tree and construct a new jQuery object from the matching elements ordered from immediate parent on up; the elements are returned in order from the closest parent to the outer ones.

Another user suggested:

.closest([selector])

Similar to .parents(), this may be a better choice as it stops once it finds the element it is looking for. Seems like it would be more efficient in this case. See http://api.jquery.com/closest/ for more details. Hope this helps people understand the differences between .closest() and .parents() and how powerful and flexible jQuery can be.

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Luminary・发光体
5楼-- · 2019-02-12 04:07

$(this).closest("ul") will traverse the parents until it finds a ul

http://docs.jquery.com/Traversing/closest#expr

...get the first element that matches the selector by testing the element itself and traversing up through its ancestors in the DOM tree...

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何必那么认真
6楼-- · 2019-02-12 04:10

$(this).parents().get()[4] will give you the fifth

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