koa2中模板调用js报错的问题

Question

index.jade文件：

doctype html
html
  head
    meta(charset='utf-8')
    title= title
    link(rel='stylesheet', href='/stylesheets/style.css')
    script(type='text/javascript', src='/javascripts/jquery-1.10.2.js')
    script(type='text/javascript', src='/javascripts/index.js')
  body
    button(onclick='test()')="点击"
    
    
index.js文件

function test(){
    console.log('test')
}

为什么这样写是报错test未定义的呢？