如何使用添加选项并排创建依赖下拉列表

I want to add 2 dropdowns list side by side. Like first dropdown for skills like HTML5,CSS3,JS,PHP etc and 2nd dropdown for levels like begineer,advanced,expert etc. I also want to have an add button so i can keep on adding more skills. Below code helps me to add 2 buttons but vertically instead of aide by side. But I want to know how to have an add button.I want to add 2 dropdowns list side by side. Li