数组转换为字符串，字符串转换为数组

var _str="abc789466";
var obj=_str.toString().replace(/(.)(?=[^$])/g,"$1,").split(",");       //字符串转化为数组
var obj2 = "new2abcdefg".split("");                                            //字符串转化为数组
alert(obj);
alert(obj.length);
alert(obj instanceof Array);
alert(obj.join(""));  //数组转化为字符串