Angularjs met $scope,xxx=function () error is undefined for this function

This bun met a problem today, is clearly written $scope,xx=function () but error, error shows that the function is undefined, I am very anxious to write a function of a global function, there is no problem, and so on in the afternoon when the time to think about, why the overall line, Later try to write before the $scope.xxx=function () on the top, found that there is no error, only to understand that the function in this angularjs is the order of execution, write call method, preferably written on top, so de si nei!

Their basic skills are not solid, have to exercise a lot AH

Angularjs met $scope,xxx=function () error is undefined for this function