js克隆函数

function clone(obj) {
var o;
if (typeof obj == "object") {
    if (obj === null) {
        o = null;
    } else {
        if (obj instanceof Array) {
            o = [];
            for (var i = 0, len = obj.length; i < len; i++) {
                o.push(clone(obj[i]));
            }
        } else {
            o = {};
            for (var j in obj) {
                o[j] = clone(obj[j]);
            }
        }
    }
} else {
    o = obj;
}
return o;
}