mui scroll 滚动时，获取scrollTop距离是NAN或者出现一大串字符串

监听scoll

let _scroll = mui('#offCanvasContentScroll').scroll();

document.getElementById('offCanvasContentScroll').addEventListener('scroll', function (e) {
sessionStorage.setItem('_scroll', _scroll.y);
})
滚动的距离值为NaN或者-301-15-63-56-3 一大串字符串

mui('#offCanvasContentScroll').scroll().refresh();
mui('#offCanvasContentScroll').scroll().scrollTo(0, _scroll,0);//_scroll 为滚动的距离