关于as3替换字符串

//replace all
var str:String="AAABBBCCCAAA";
str=str.split("AAA").join("DDD");
//结果str为：DDDBBBCCCDDD

//replace first
var str:String="AAABBBCCCAAA";
str=str.replace("AAA","DDD");
//结果str为：DDDBBBCCCAAA