How to detect that one class has touched the other? [duplicate]

I have a question regarding the detection of classes in Jquery. For example. I'm developing a land page and in it has the navbar that when it arrives in certain parts of the site it changes color, only that it has a problem, I'm doing it in a way that only works on a 21-inch monitor and it's not going to give anything right . I'd like to know which command I can use to detect that for example the "navbar" class has arrived in the "Where to find" class. So that I can change the color without worrying about the device that is using the site.