The ||
is the if statement in this case. If window.jQuery
returns TRUE
, then anything after the or
statement (||) won't get loaded. If it's FALSE
, then it'll continue on to load jquery.
Edit: Just to clarify a bit. If you do if (var1 && var2)
in javascript, it'll evaluate BOTH variables to check if they're both true. If you make it if (var1 || var2)
, then if the first variable evaluates to TRUE, there's no need to evaluate the rest of the expression, since it'll automatically be true either way.
In this case, that's exactly what your code is doing. If window.jQuery
is FALSE (meaning jQuery wasn't loaded), then continue on and evaluate the next expression--which in this case loads the jquery from a local file. It's just not wrapped in an IF statement since it's not necessary.