You can find many examples on Internet where you can see that focusout and blur events are used as synonyms and you can be confused with their usage.

What is difference between jQuery's .focusout() and .blur() events?

The difference between .focusout() and blur() jQuery event is that the .focusout() is sent to an element when it, or any element inside of it, loses focus. The .blur() event supports detecting the loss of focus from parent elements (i.e., it supports event bubbling)

What is event bubbling

Event bubbling in jQuery represents propagating event fired in one element to upper or lower elements in DOM hierarchy.