jQuery粘性顶部菜单栏请求

Question

Im looking for a jQuery pluging (or code/guide) that does this: http://codecanyon.net/item/jquery-css3-sticky-mega-menu-bar/full_screen_preview/239093

This one is not free

Note: Notice the navigation bar is not placed at the top from the beginning. It sticks once the viewport "hits" it.

Answer 1

Anthony Garand also has a pretty sticky plugin - All free and actually maintained on GitHub:

jQuery Sticky Plugin

Answer 2

You could reverse engineer @genesis link which is the exact script you are looking for (no it is not hard)

I couldn't find a url for a non-minified version.. so here it is.

(function ($) {
    $.fn.stickyMenubar = function (o) {
        o = $.extend({
            top: null,
            floatingDiv: null,
            floatingDivBackground: false,
            megaMenu: true,
            onScroll: function () {},
            onLeaveTop: function () {},
            sensitivity: 7,
            padding: 5,
            container_width: 960
        }, o || {});
        var setLiActions = function (t, lvl) {
                var parent_ul = t.children('ul:first');
                if (lvl > 0) {
                    t.addClass('inner_menu').hide();
                } else {
                    if (!o.floatingDivBackground) {
                        t.addClass('smenubar_background');
                    }
                }
                t.mouseleave(function () {
                    $(this).children('li').children('ul').hide();
                });
                t.children('li').each(function () {
                    var li = $(this);
                    var class_parent = '';
                    var class_child = '';
                    var uls = li.children('ul');
                    if (uls.length) {
                        uls.each(function () {
                            setLiActions($(this), lvl + 1);
                        })
                        if (lvl == 0) {
                            li.children('a:first').addClass('arrow_down');
                        } else {
                            li.children('a:first').addClass('arrow_right');
                        }
                        if (!$.fn.hoverIntent) {
                            alert('hoverIntent javascript library must be included');
                            return;
                        }
                        var config = {
                            over: function () {
                                if (lvl == 0) {
                                    $(this).parent().children('li').not($(this)).children('ul').hide();
                                    var inner_ul = li.children('ul:first');
                                    var pos = li.position();
                                    var pos_ul = inner_ul.position();
                                    var top_c = pos.top + li.height();
                                    if (inner_ul.hasClass('show2left')) {
                                        var left_c = pos.left - inner_ul.width() + li.width() + (o.padding * 2);
                                        class_parent = 'inuseleft';
                                        class_child = 'inusechildleft';
                                        class_panel = 'left_slide';
                                        inner_ul.addClass('topleftradius')
                                    } else if (inner_ul.hasClass('mega_menu')) {
                                        var left_c = 0 + ($(document).width() / 2) - (o.container_width / 2);
                                        class_parent = 'inusemega', class_child = 'inusechildmega';
                                        class_panel = 'mega_slide';
                                        inner_ul.addClass('topleftradius').addClass('toprightradius');
                                    } else {
                                        var left_c = pos.left;
                                        class_parent = 'inuse';
                                        class_child = 'inusechild';
                                        class_panel = 'right_slide';
                                        inner_ul.addClass('toprightradius');
                                    }
                                    if (!$.browser.msie || ($.browser.msie && ($.browser.version > 7.0))) {
                                        if (inner_ul.width() <= (li.width() + (o.padding * 2))) {
                                            inner_ul.css('width', li.width() + (o.padding * 2));
                                            inner_ul.removeClass('topleftradius').removeClass('toprightradius');
                                        }
                                    }
                                    inner_ul.stop(true, true).css({
                                        top: top_c,
                                        left: left_c
                                    }).addClass(class_panel).slideDown(150);
                                    li.addClass(class_child);
                                } else {
                                    var inner_ul = li.children('ul');
                                    var pos = li.position();
                                    var pos_ul = inner_ul.position();
                                    var top_c = pos.top;
                                    if (inner_ul.hasClass('show2left')) {
                                        var left_c = pos.left - inner_ul.width() + li.width() - 1;
                                        class_parent = 'inuseleft';
                                        class_child = 'inusechildleft';
                                        class_panel = 'left_slide';
                                    } else {
                                        var left_c = pos.left + li.width();
                                        if ($.browser.mozilla) {
                                            left_c--;
                                        }
                                        class_parent = 'inuse';
                                        class_child = 'inusechild';
                                        class_panel = 'right_slide';
                                    }
                                    inner_ul.css({
                                        top: top_c,
                                        left: left_c
                                    }).addClass(class_panel).css({
                                        'white-space': 'nowrap'
                                    }).stop(true, true).animate({
                                        width: 'toggle'
                                    }, 300);
                                    li.addClass(class_child);
                                }
                            },
                            sensitivity: o.sensitivity,
                            timeout: 200,
                            out: function () {
                                li.stop(true, true).removeClass(class_child).children('ul').hide();
                            }
                        };
                        li.each(function () {
                            $(this).hoverIntent(config);
                            $(this).mouseleave(function () {
                                if (lvl == 0) {
                                    $(this).children('ul').hide();
                                }
                            });
                        });
                    } else {
                        li.mouseenter(function () {
                            li.stop(true, true).addClass(class_parent);
                        });
                        li.mouseleave(function () {
                            li.stop(true, true).removeClass(class_parent).children('ul').hide();
                        });
                    }
                });
            }
        return this.each(function () {
            var t = $(this);
            t.addClass('smenubar');
            if (!o.floatingDiv) {
                var floatingDiv = t;
            } else {
                var floatingDiv = o.floatingDiv;
                floatingDiv.css({
                    width: '100%'
                });
            }
            var top_Y = 0;
            if (!o.top) {
                top_Y = floatingDiv.position().top;
            } else {
                top_Y = o.top;
            }
            if (o.floatingDivBackground) {
                floatingDiv.addClass('smenubar_background');
                t.css({
                    'border-bottom': 'none'
                });
            }
            $(window).scroll(function () {
                if ($(this).scrollTop() >= top_Y) {
                    if (!($.browser.msie && ($.browser.version <= 7.0))) {
                        floatingDiv.addClass('float_top');
                        o.onLeaveTop.call(this);
                    }
                } else {
                    floatingDiv.removeClass('float_top').removeClass('float_top_ie7');
                    o.onScroll.call(this);
                }
                var open_menu = $('.inner_menu:visible');
                var parent_li = open_menu.parent();
                var pos = parent_li.position();
                open_menu.css({
                    top: pos.top + parent_li.height()
                });
            });
            t.find('.toggle_block').slideToggle();
            t.find('.toggle_handle').html('...').css('text-align', 'center');
            t.find('a').click(function () {
                if ($(this).hasClass('toggle_handle')) {
                    var prev = $(this).parent().prev('.toggle_block');
                    prev.slideToggle().prevUntil(':not(.toggle_block)').slideToggle();
                }
                if ($(this).attr('href') == '#') {
                    event.preventDefault();
                    return;
                }
            });
            if (o.megaMenu == true) {
                setLiActions(t, 0);
            }
        });
    };
})(jQuery);

play around with it. generally these plugins are very scale-able and customize-able so there is a bunch of junk code in there. The majority of what you want seems to be encased in

(window).scroll(function () {
                if ($(this).scrollTop() >= top_Y) {
                    if (!($.browser.msie && ($.browser.version <= 7.0))) {
                        floatingDiv.addClass('float_top');
                        o.onLeaveTop.call(this);
                    }
                } else {
                    floatingDiv.removeClass('float_top').removeClass('float_top_ie7');
                    o.onScroll.call(this);
                }
                var open_menu = $('.inner_menu:visible');
                var parent_li = open_menu.parent();
                var pos = parent_li.position();
                open_menu.css({
                    top: pos.top + parent_li.height()
                });
            });