replace深入

var b = 0;
var arr = [];
str = str.replace(/J/g,function(){
    var args = arguments;
    b++;
    arr.push(args[1]);
    return '#';
});

console.log(str+"：共替换" + b + "个，替换位置：" + arr.join());
//#ack Zhao #ust Me：共替换2个，替换位置：0,10