CSS3+jQuery实现菜单点击波纹涟漪效果

这是一个是点击时波纹涟漪特效的代码，一个圆圈元素从用户点击的位置径向扩散开来。大概原理是在单击“坐标”后面的“父项”与“父项”的链接后面创建一个圆圈元素（隐藏的）。最初是按比例缩小到0%，然后动画到250%，以覆盖整个父元素。随着圆圈的增加，其透明度开始下降。

HTML

<h1>Ripple Click Effect</h1>
<ul>
	<li><a>Dashboard</a></li>
	<li><a>My Account</a></li>
	<li><a>Direct Messages</a></li>
	<li><a>Chat Rooms</a></li>
	<li><a>Settings</a></li>
	<li><a>Logout</a></li>
</ul>

CSS

/*custom fonts - Bitter, Montserrat*/
@import url('http://fonts.useso.com/css?family=Montserrat|Bitter');
h1 {
	font: normal 32px/32px Bitter; color: white;
	text-align: center; padding: 85px 100px;
}

/*nav styles*/
ul {
	background: white; border-top: 6px solid hsl(180, 40%, 60%);
	width: 200px; margin: 0 auto;
}
ul li {
	list-style-type: none;
	/*relative positioning for list items along with overflow hidden to contain the overflowing ripple*/
	position: relative;
	overflow: hidden;
}
ul li a {
	font: normal 14px/28px Montserrat; color: hsl(180, 40%, 40%);
	display: block; padding: 10px 15px;
	text-decoration: none;
	cursor: pointer; /*since the links are dummy without href values*/
	/*prevent text selection*/
	user-select: none;
	/*static positioned elements appear behind absolutely positioned siblings(.ink in this case) hence we will make the links relatively positioned to bring them above .ink*/
	position: relative;
}

/*.ink styles - the elements which will create the ripple effect. The size and position of these elements will be set by the JS code. Initially these elements will be scaled down to 0% and later animated to large fading circles on user click.*/
.ink {
	display: block; position: absolute;
	background: hsl(180, 40%, 80%);
	border-radius: 100%;
	transform: scale(0);
}
/*animation effect*/
.ink.animate {animation: ripple 0.65s linear;}
@keyframes ripple {
	/*scale the element to 250% to safely cover the entire link and fade it out*/
	100% {opacity: 0; transform: scale(2.5);}
}

javascript

//jQuery time
var parent, ink, d, x, y;
$("ul li a").click(function(e) {
    parent = $(this).parent();
    //create .ink element if it doesn't exist
    if (parent.find(".ink").length == 0)
        parent.prepend("<span class='ink'></span>");

    ink = parent.find(".ink");
    //incase of quick double clicks stop the previous animation
    ink.removeClass("animate");

    //set size of .ink
    if (!ink.height() && !ink.width()) {
        //use parent's width or height whichever is larger for the diameter to make a circle which can cover the entire element.
        d = Math.max(parent.outerWidth(), parent.outerHeight());
        ink.css({
            height: d,
            width: d
        });
    }

    //get click coordinates
    //logic = click coordinates relative to page - parent's position relative to page - half of self height/width to make it controllable from the center;
    x = e.pageX - parent.offset().left - ink.width() / 2;
    y = e.pageY - parent.offset().top - ink.height() / 2;

    //set the position and add class .animate
    ink.css({
        top: y + 'px',
        left: x + 'px'
    }).addClass("animate");
})