jquery - 没有插件的脉冲 jquery

Question

我有一个简单的淡入淡出，我想无限期地进出。我找到了可以执行此操作的插件，但很好奇 jquery 是否已经有一个 Loop() api，这样我就可以在脚本中处理它。

<script type="text/javascript">
$(document).ready(function(){    
    $('.bottom-left').delay(1000).fadeIn(900);
    $('.bottom-right').delay(3000).fadeIn(700);
});
</script>

Answer 1

如果您想使其变得复杂，那么这可能会变成很多代码，但简单的实现只需几行。基本上，您想要递归调用一个函数，该函数隐藏或显示动画函数的回调函数中的元素:

$(function () {

    //declare a function that can fade in/out any element with a specified delay and duration
    function run_animation($element, delay, duration) {

        //animate fade in/out after delay
        $element.delay(delay).fadeToggle(duration, function () {

            //after fade in/out is done, recursively call this function again with the same information
            //(if faded-out this time then next-time it will be faded-in)
            run_animation($element, delay, duration);
        });
    }

    //initialize the animations for each element, specifying a delay and duration as well
    run_animation($('.bottom-left'), 1000, 900);
    run_animation($('.bottom-right'), 3000, 700);
});

这是一个演示:http://jsfiddle.net/xpw4D/

.fadeToggle() 的文档:http://api.jquery.com/fadeToggle

更新

您可以稍微增强此代码并为两个以上的步骤设置动画，如下所示:

$(function () {

    function run_animation(options) {

        //initialize the count variable if this is the first time running and reset it to zero if there are no more steps
        if (typeof options.count == 'undefined' || options.count >= options.steps.length) {
            options.count = 0;
        }

        options.element.delay(options.steps[options.count].delay).fadeToggle(options.steps[options.count].duration, function () {

            options.count++;

            run_animation(options);
        });
    }

    run_animation({
        element  : $('.bottom-left'),
        steps    : [
            { delay : 1000, duration : 100 },
            { delay : 500, duration : 900 },
            { delay : 3000, duration : 500 }
        ]
    });
    run_animation({
        element  : $('.bottom-right'),
        steps    : [
            { delay : 2000, duration : 200 },
            { delay : 1000, duration : 1800 },
            { delay : 6000, duration : 1000 }
        ]
    });
});​

这是一个演示:http://jsfiddle.net/jasper/xpw4D/2/