Question about working of External javascript

Question

Hi All,

I had a question regarding the working of an external javascript file
Suppose I have an external javascript file and it has a set of functions written in it. I reference this JS file in my HTML page. Now, when a user requests for this HTML page, what happens with the JS file. Is the function body that is called from the HTML sent with the page markup ? or is the JS file downloaded to the users machine/ loaded in the memory ??

Regards,
Vipul