JavaScript中，快速实现一个对象的复制！

1、第一种方式，通过JSON转换。

function clone (src) {
    return JSON.parse(JSON.stringify(src));
}

注意，需要引入JSON库：
https://github.com/douglascrockford/JSON-js

2、第二种方式，通过编写JavaScript方法：

function clone(src) {
  function mixin(dest, source, copyFunc) {
    var name, s, i, empty = {};
    for(name in source){
      // the (!(name in empty) || empty[name] !== s) condition avoids copying properties in "source"
      // inherited from Object.prototype.   For example, if dest has a custom toString() method,
      // don't overwrite it with the toString() method that source inherited from Object.prototype
      s = source[name];
      if(!(name in dest) || (dest[name] !== s && (!(name in empty) || empty[name] !== s))){
        dest[name] = copyFunc ? copyFunc(s) : s;
      }
    }
    return dest;
  }

  if(!src || typeof src != "object" || Object.prototype.toString.call(src) === "[object Function]"){
    // null, undefined, any non-object, or function
    return src;  // anything
  }
  if(src.nodeType && "cloneNode" in src){
    // DOM Node
    return src.cloneNode(true); // Node
  }
  if(src instanceof Date){
    // Date
    return new Date(src.getTime());  // Date
  }
  if(src instanceof RegExp){
    // RegExp
    return new RegExp(src);   // RegExp
  }
  var r, i, l;
  if(src instanceof Array){
    // array
    r = [];
    for(i = 0, l = src.length; i < l; ++i){
      if(i in src){
        r.push(clone(src[i]));
      }
    }
    // we don't clone functions for performance reasons
    //    }else if(d.isFunction(src)){
    //      // function
    //      r = function(){ return src.apply(this, arguments); };
  }else{
    // generic objects
    r = src.constructor ? new src.constructor() : {};
  }
  return mixin(r, src, clone);

}