delay further processing until "if statement" executed, in javascript -

delay further processing until "if statement" executed, in javascript -

i have "if statement" so:

if (webservice returns true) { alert("booyah"); } alert("hooray");

trouble webservice slow. , "hooray" gets triggered before "booyah" when webservice returns true.

how can pause farther processing until "if statement" evaluated?

i'm thinking kind of callback function might needed here. how construction it?

additionally, there way have wait animation on webpage while "if statement" beingness waited on?

javascript if-statement callback