用browserify生成的js文件引用后报错Uncaught ReferenceError: require is not defined

用browserify生成的js文件，在浏览器中引用后老报错，
Uncaught ReferenceError: require is not defined
不知道是什么原因。

---

错误信息指的是require没有定义，说明你需要在bundle.js外部使用require，那么你生成的时候应该使用下面的方式生成。

external requires

You can just as easily create bundle that will export a require() function so
you can require() modules from another script tag. Here we'll create a
bundle.js with the through
and duplexer modules.

$ browserify -r through -r duplexer -r ./my-file.js:my-module > bundle.js

Then in your page you can do:

<script src="bundle.js"></script>
<script>
  var through = require('through');
  var duplexer = require('duplexer');
  var myModule = require('my-module');
  /* ... */
</script>