这是一款jquery和CSS3圆形倒计时特效。该特效使用CSS对页面进行布局，生成用于倒计时的圆环，然后通过jquery代码来控制圆环的倒计时进度。

使用方法

在页面中引入下面的文件。

<link href="css/style.css" rel="stylesheet" />
<script src="js/jquery.min.js" type="text/javascript"></script>
HTML结构
<div class="flex-container">
    <div class="outbox">
    </div>
    <!--  SVG AREA -->
    <svg class="svg">
        <circle id="cls" class="cls run-anim" cx="130" cy="130" r="125"></circle>
    </svg>
    <!--  SVG AREA END -->
    <div class="control">
        <div class="time">
            <label for="min">
                Min
                <input id="min" type="number" min="0" max="59" placeholder="mm" value="0" />
            </label>
            <label for="sec">
                Sec
                <input id="sec" type="number" min="0" max="59" placeholder="ss" value="0" />
            </label>
        </div>
        <div class="action">
            <button id="start" class="">
                开始
            </button>
    <button id="reset" class="">
        停止
    </button>
        </div>
    </div>
</div>
初始化插件
let circle = document.getElementById('cls');
let total ;
let start = $('#start');

start.click( ()=>{
    let minute = document.getElementById('min').value;
    let second = document.getElementById('sec').value;
    // console.log("seconds:"+(minute*60)+"secs:"+second);
    total = (parseInt(minute)*60) + parseInt(second);
    console.log("total:"+total);
    circle.style.strokeDashoffset = "800";
    circle.style.animationDuration = total+"s";
    circle.style.animationPlayState = "running";
    set(1000*total);
    circle.classList.add("run-anim");
});

function set(total){
    let interval = setInterval(ret,total);
    function ret(){
        confirm('Timer Completed! Press Reset');
        circle.classList.remove("run-anim");
        void circle.offsetWidth;
        clearInterval(interval);
    }
}

// let reset = $('#reset');
// reset.click(()=>{
//     circle.style.animationPlayState = "paused";
// });

该jquery和CSS3圆形倒计时特效的github网址为：https://github.com/Bhanu8047/Timer-Animation