Jquery实现无限级别导航菜单插件
dengjianbin
12年前
Jquery实现无限级别导航菜单插件是一款功能很功能且很实用的插件，做网站不可缺少的神兵利器之一，刚好最近有位上海的网友留言需要一个3级的导航菜单，为了满足更多网友的需求，漫画就去收集了此插件，有了它之后你想导航菜单有多少子菜单都可以，使用超简单，引入插件之后，写一句初始化脚就可以实现了，讲了这么多，网友们都流口水了吧，先看效果
效果如下：
插件代码如下：
;(function($){ // $ will refer to jQuery within this closure $.fn.supersubs = function(options){ var opts = $.extend({}, $.fn.supersubs.defaults, options); // return original object to support chaining return this.each(function() { // cache selections var $$ = $(this); // support metadata var o = $.meta ? $.extend({}, opts, $$.data()) : opts; // get the font size of menu. // .css('fontSize') returns various results cross-browser, so measure an em dash instead var fontsize = $('<li id="menu-fontsize">—</li>').css({ 'padding' : 0, 'position' : 'absolute', 'top' : '-999em', 'width' : 'auto' }).appendTo($$).width(); //clientWidth is faster, but was incorrect here // remove em dash $('#menu-fontsize').remove(); // cache all ul elements $ULs = $$.find('ul'); // loop through each ul in menu $ULs.each(function(i) { // cache this ul var $ul = $ULs.eq(i); // get all (li) children of this ul var $LIs = $ul.children(); // get all anchor grand-children var $As = $LIs.children('a'); // force content to one line and save current float property var liFloat = $LIs.css('white-space','nowrap').css('float'); // remove width restrictions and floats so elements remain vertically stacked var emWidth = $ul.add($LIs).add($As).css({ 'float' : 'none', 'width' : 'auto' }) // this ul will now be shrink-wrapped to longest li due to position:absolute // so save its width as ems. Clientwidth is 2 times faster than .width() - thanks Dan Switzer .end().end()[0].clientWidth / fontsize; // add more width to ensure lines don't turn over at certain sizes in various browsers emWidth += o.extraWidth; // restrict to at least minWidth and at most maxWidth if (emWidth > o.maxWidth) { emWidth = o.maxWidth; } else if (emWidth < o.minWidth) { emWidth = o.minWidth; } emWidth += 'em'; // set ul to width in ems $ul.css('width',emWidth); // restore li floats to avoid IE bugs // set li width to full width of this ul // revert white-space to normal $LIs.css({ 'float' : liFloat, 'width' : '100%', 'white-space' : 'normal' }) // update offset position of descendant ul to reflect new width of parent .each(function(){ var $childUl = $('>ul',this); var offsetDirection = $childUl.css('left')!==undefined ? 'left' : 'right'; $childUl.css(offsetDirection,emWidth); }); }); }); }; // expose defaults $.fn.supersubs.defaults = { minWidth : 9, // requires em unit. maxWidth : 25, // requires em unit. extraWidth : 0 // extra width can ensure lines don't sometimes turn over due to slight browser differences in how they round-off values }; })(jQuery);