Javascript error, behavior / general.js

I have the following error accusing in browser mode

Uncaught TypeError: undefined is not a function general.js:1549
init general.js:1549
(anonymous function) login:542
c jquery.js:4
p.fireWith jquery.js:4
x.extend.ready jquery.js:4
q

I did not find anything that would help me and my application behaves strangely.

Update

code in page haml

%a{:href => "http://www.site.com.br"} © 2014 empresa
%script{:src => "js/jquery.js"}
%script{:src => "js/behaviour/general.js", :type => "text/javascript"}

function in the .js file that the error points to:

if(config.select2){
    $(".select2").select2({
        width: '100%'
    });
}