What is the difference between $ and $$?

Question

I have been going through some jQuery functionality.

Can any one please give me some idea of what the difference is between the use of $ and $$

Answer 1

Short Anser: $$ is NOT defined in jQuery specifications, in addition the notation of single $( ) - sign means you encapsulate things inside bracket to a jQuery object.

Thus, alias $ is an abbreviation to say - i am using jQuery library, where as double $$ is not defined in a standard jQuery library.