jquery gets an element with the same class name as a child element in a div element

In the recent map function, you need to add a click event in the pop-up window of the click device

Because I use a third-party map, the pop-up window is hard-coded, and the pop-up window cannot be customized. It must follow the format of the other party, so I can only superimpose the function by myself. What I want to achieve is to click on a certain pop-up window Element, open another second-level pop-up window page. Currently, you can only use jquery to select elements, add click event processing, and later have time to study how to realize the pop-up window function by yourself. At present, it is handled like this

I haven't used jquery for a long time, and I forgot how to get elements, so I will record it here

$('ul').find('li:first');
$('ul li:first');
$('ul li').eq(0);

These methods are commonly used jquery to get the first method of an element