javascript not running

gistfile1.txt

show.html.erb

<% content_for :javascript_includes do %>
  <%= javascript_include_tag "colleges.js" %>
<% end %>

application.html.haml

!!!
%html
  %head
    %title= yield(:title)
    = csrf_meta_tag
    = javascript_include_tag "application"
    = stylesheet_link_tag    "application"
    = yield :javascript_includes

assets/javascripts/colleges.js

var height = $("#college_public_chat").prop('scrollHeight');
$("#college_public_chat").scrollTop(height);