html选择下拉滚动条 - 仅当下拉框存在时

Is there a way to place a scrollbar inside an html 'select' and 'option' area? I only want the scrollbar to appear when the dropdown menu is clicked. I have set max-height and overflow's appropriately (at least according to Google search result articles and Stackoverflow responses) but nothing seems to change. I do not want the max-height or height to effect the loaded size. Is there a way to place a scrollbar inside an h