javascript，对JavaScript中的5种主要的数据类型（包括Number、String、Object、Array、Boolean）进行值复制

var clone = function(obj){
var buf;
if(obj instanceof Array){
buf = [];
var i = obj.length;
while(i--){
buf[i] = obj[i];
}
return buf;
}else if(obj instanceof Object){
buf = {};
for(var k in obj){
buf[k] = clone(obj);
}
return buf;
}else{
return obj;
}
};

Object.prototype.clone = function(){
var o = this.constructor === Array ?[]:{};
for(var e in this){
o[e] = typeof this[e] === 'object'?this[e].clone:this[e];
}
return o;
};