js计时器

计时器

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第一种：根据页面时间倒计时

(function(){
    var startCountDown = function(){
        var hours = parseInt($("#J_hour").text());
        var minutes = parseInt($("#J_minute").text());
        var seconds = parseInt($("#J_second").text());
        if (seconds <= 0) {
            if (minutes <= 0) {
                if (hours <= 0) {
                    alert("时间结束！");
                    return ;
                } else {
                    hours--;
                }
                minutes = 59;
            } else {
                minutes--;
            }
            seconds = 59;
        } else {
            seconds--;
        }
        $("#J_second").html((seconds).toString().length > 1 ? seconds : "0" + seconds);
        $("#J_minute").html((minutes).toString().length > 1 ? minutes : "0" + minutes);
        $("#J_hour").html((hours).toString().length > 1 ? hours : "0" + hours);
        time = setTimeout(startCountDown, 1000);
    };
    window.startCountDown = startCountDown;
})();

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第二种：js指定时间倒计时

(function(){
    var seconds = 60; // 可配置
    var startCountDown = function(){
        if (seconds <= 0) {
            console.log("获取超时!");
        } else {
            console.log("请耐心等待(" + (seconds--) + "s)");
        }
        time = setTimeout(startCountDown, 1000);
    };
    window.startCountDown = startCountDown;
})();