解决ios微信下软键盘收起后，页面留白

  //解决底部空白
    (function () {
        let myFunction
        let isWXAndIos = isWeiXinAndIos()
        if (isWXAndIos) {
            document.body.addEventListener('focusin', () => {
                clearTimeout(myFunction)
            })
            document.body.addEventListener('focusout', () => {
                clearTimeout(myFunction)
                myFunction = setTimeout(function() {
                    window.scrollTo({top: 0, left: 0, behavior: 'smooth'})
                }, 200)
            })
        }
    })();
    function isWeiXinAndIos () {
        let ua = '' + window.navigator.userAgent.toLowerCase()
        let isWeixin = /MicroMessenger/i.test(ua)
        let isIos = /\(i[^;]+;( U;)? CPU.+Mac OS X/i.test(ua)
        return isWeixin && isIos
    }
   
    //解决底部空白 end