克隆JS对象的三个实用方法

方法一

    function clone(obj){  
        var o;  
        switch(typeof obj){  
        case 'undefined': break;  
        case 'string'   : o = obj + '';break;  
        case 'number'   : o = obj - 0;break;  
        case 'boolean'  : o = obj;break;  
        case '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 k in obj){  
                        o[k] = clone(obj[k]);  
                    }  
                }  
            }  
            break;  
        default:          
            o = obj;break;  
        }  
        return o;     
    }  

方法二

    function clone2(obj){  
        var o, obj;  
        if (obj.constructor == Object){  
            o = new obj.constructor();   
        }else{  
            o = new obj.constructor(obj.valueOf());   
        }  
        for(var key in obj){  
            if ( o[key] != obj[key] ){   
                if ( typeof(obj[key]) == 'object' ){   
                    o[key] = clone2(obj[key]);  
                }else{  
                    o[key] = obj[key];  
                }  
            }  
        }  
        o.toString = obj.toString;  
        o.valueOf = obj.valueOf;  
        return o;  
    }  

方法三

    function clone3(obj){  
        function Clone(){}  
        Clone.prototype = obj;  
        var o = new Clone();  
        for(var a in o){  
            if(typeof o[a] == "object") {  
                o[a] = clone3(o[a]);  
            }  
        }  
        return o;  
    }  

http://snandy.iteye.com/blog/842097