textarea根据内容自动调节高度时不同浏览器显示问题

Question

 $.fn.autoHeight = function(){
        function autoHeight(elem){
            elem.style.height = 'auto';
            elem.scrollTop = 0; //防抖动
            elem.style.height = elem.scrollHeight + 'px';
        }
        this.each(function(){
            autoHeight(this);
            $(this).on('keyup', function(){
                autoHeight(this);
            });
        });
    }
    $('textarea[autoHeight]').autoHeight();
``
html加入autoHeight="true"
此时打开ie浏览器，显示如下
![图片说明](https://img-ask.csdn.net/upload/201911/01/1572575259_832844.jpg)
这是显示正常，当用谷歌浏览器打开时显示如下
![图片说明](https://img-ask.csdn.net/upload/201911/01/1572575301_821595.jpg)
求助大佬这是什么原因