JQuery使用选择选项和CSS

I am setting two select options and customizing these options with CSS and JQuery. The issue that is happening is when selecting the options, you need to 'click' on the upper left corner of the select option, and then the options dont show gracefully, they slide out from the middle of the select box. Is there a method to ensure that anywhere you click on the select option, the drop down will populate and is there a method to ensure the drop down appears from the bottom of the select box, as opposed to coming horizontally out of the select?I am setting two select options and customizing