禁止页面回弹

　　//控制页面不动

　　bounce: false

    var heightSum = document.documentElement.clientHeight;

    var first = document.getElementsByClassName('first')[0];

    var second = document.getElementsByClassName('second')[0];

    var firstHeight = first.clientHeight;

    second.style.height = (heightSum - firstHeight) + 'px';

    second.style.overflow = 'scroll';