滚动时固定元素触底停止，Safari 11.1兼容的jQuery方案需求

Hey folks, here's an update on my journey to get that sticky sidebar working properly:

• I’ve tested using CSS position: sticky, but it completely fails to work in Safari 11.1.
• Since Safari makes up the largest share of our user base, a pure CSS approach just isn’t going to cut it for us. I’m still hunting for a jQuery-based solution instead.
• While Michał Sadowski’s answer was super helpful in pointing me in some good directions, what I actually need is a specific behavior: the sidebar should stay fixed as the user scrolls, but once it reaches the footer, it should stop being fixed and scroll along with the rest of the page.
• Currently, I’m referencing the code from the solution called Make scrolling sidebar stop at footer—my CSS and HTML match exactly what’s in the fiddle example for that solution.

内容的提问来源于stack exchange，提问作者Jay-oh