How to know variables from different…“namespaces”?

Question

How can I reach some variable declared in another place from within an external javascript file ?

Suppose in an html file I have the following

Answer 1

when a variable is defined without var it is said to exist in global scope. When your JS is loaded into your page, it is aware of any variables that exist globally at that time. So, what google is doing is defining some variables and then loading in an external script.