Using Dropdowns with Jade and Bootstrap gives me $(".dropdown-toggle").dropdown is not a function

Question

I'm trying to get a Bootstrap dropdown working with my Jade layout. But actually I'm getting this error when I'm trying to execute $(".dropdown-toggle").dropdown in my Jade-File:

$ is undefined 
$(".dropdown-toggle").dropdown is not a function

Why do I get this error message?

layout.jade

!!! 5
html
  head
    title= title
    link(rel='stylesheet', href='/lib/bootstrap/css/bootstrap.min.css')

        script(src='lib/bootstrap/js/bootstrap.min.js')
        script(src='lib/jquery/jquery-1.7.1.min.js')

        meta(name='viewport', content='width=device-width', initial-scale='1.0')

    body!= body

index.jade

  div.navbar.navbar-fixed-top
  div.navbar-inner
    div.container
      a(data-toggle='collapse',data-target='.nav-collapse').btn.btn-navbar
      a(href='#').brand #{title}
      div.nav-collapse
        ul.nav
          li.active
            a(href='#') Home
          li
            a(href='#') Blog
          li
            a(href='#') Contact
          li(id='menu1').dropdown
            a(data-toggle='dropdown', href='#menu1').dropdown-toogle Dropdown
              b.caret
            ul.dropdown-menu
              li
                a(href='#') Test
              li
                a(href='#') Test2

script
  $('.dropdown-toggle').dropdown()

Answer 1

You need to load the jQuery core before the bootstrap -

script(src='lib/jquery/jquery-1.7.1.min.js')    
script(src='lib/bootstrap/js/bootstrap.min.js')