jquery如何实现金币下落

//定义金币下落初始位置和终止位置var coin = $("div.coin");var coinTop = coin.offset().top;var coinLeft = coin.offset().left;var coinWidth = coin.width();var coinHeight = coin.height();var endTop = $("div.end").offset().top + $("div.end").height();var endLeft = $("div.end").offset().left - coin.width();var zIndex = 1000;//定义金币掉落方式function down(){    var coinNew = $('<div class="coin"></div>');    coinNew.css({"top":coinTop,"left":coinLeft,"z-index":zIndex++});    $("body").append(coinNew);    coinNew.animate({top:endTop,left:endLeft},500,function(){        $(this).remove();    });}//定义随机掉落方式function range(min,max){    return Math.floor(Math.random() * (max - min) + min);}function leftRange(){    var maxLeft = $("body").width() - coinWidth;    var minLeft = 0;    return range(minLeft, maxLeft);}function rotateRange(){    var maxDeg = 45;    var minDeg = -45;    return "rotateZ(" + range(minDeg ,maxDeg) + "deg)";}//实现点击事件，让金币运动起来$(".start").click(function(){    var set = setInterval(function(){        down();     },50);    setTimeout(function(){        clearInterval(set);    },1500);    setTimeout(function(){        coin.css({            "top": coinTop,            "left": coinLeft,            "transform":"rotateZ(0deg)"        });    },2000);    for(var i = 0;i < 10;i++){         var coinNew = $('<div class="coin"></div>');        coinNew.css({            "top": 0 - coinHeight * 2,            "left": leftRange(),            "transform": rotateRange(),            "z-index": zIndex++        });        $("body").append(coinNew);        coinNew.animate({top:endTop,left:endLeft},500,function(){            $(this).remove();        });    }});