代码正确缩进位置如下，

extend "layout"block 'content',->   div ->'nihao'   script id:"InvoiceItem",type:"text/template",style:"display: none",->        div ->"{
   {price}}"        div ->"{
   {quantity}}"        div ->"{
   {amount}}"   coffeescript ->      $ ->        invoiceItemModel = new InvoiceItemModel({price:5,quantity:3})        (new PreviewInvoiceItemView({el:'body',model:invoiceItemModel})).render()

原因：引用了extend "layout"模板以后，要操作当前页面的代码，应该放在当前页面代码的内部，放在外部是访问不到的，所以报错：Uncaught TypeError: Cannot read property 'replace' of undefined