js实现 数字变化效果

代码：

setInterval(function () {    var material=Math.random()*(2000-1119+1)+1119;    material=Math.round(material);    $(".material").html(material);    var people=Math.random()*(2000-1119+1)+1119;    people=Math.round(people);    $(".people").html(people);    var design=Math.random()*(2000-1119+1)+1119;    design=Math.round(design);    $(".design").html(design);    var quality=Math.random()*(2000-1119+1)+1119;    quality=Math.round(quality);    $(".quality").html(quality);    var maxfont=material+people+design+quality;    $(".maxfont").html(maxfont);},500);

Math.random()*(2000-1119+1)+1119;  得到1119-2000之间的一个随机值