獲取元素與屏幕左邊框left與上邊框top的距離

function getLeftAndTop(divId){
    let dom  = document.getElementById(divId)
    let left = dom.getBoundingClientRect().left + 'px'
    let top = dom.getBoundingClientRect().top + 'px'
    return {left:left,top:top}
},