underscore.string下载正确引用后为什么会报错，非node方式

Question

<meta charset="utf-8"/><script src="../underscore.js"></script><script src="../underscore.string.js"></script><script src="../jquery.js"></script><script src="../backbone.js"></script><script>//TypeError: _(...).chain(...).trim is not a function    console.log(_("   epeli  ").chain().trim().capitalize().value());</script>

Answer 1

var test = "   this is a test    ";

console.log(test);    // "   this is a test    "

test = _.str.trim(test);

console.log(test);    // "this is a test"

test = _.str.capitalize(test);

console.log(test);    // "This is a test"