当滚动条滚动到页面某个位置时，触发js,

$(window).scroll(function(){
    //window.onload = function() {
        //setup CountUp object

        demo = new CountUp('myTargetElement', 0, 30, 0, 2, options);
        demo1 = new CountUp('yingyong', 0, 100, 0, 2, options);
        demo2 = new CountUp('qiye', 0, 20000, 0, 2, options);
        demo.start();
        demo1.start();
        demo2.start();
        //document.getElementById('version').innerHTML = 'v'+demo.version();            

    });   
$(window).scroll(function(){
    if ($(window).scrollTop()>200) {
        //code........

    }
});