【把数组转成字符串】
应用String.join（）办法:
[sourcecode language="plain"]
var myArr:Array = new Array（"one"， "two"， "three"）;
var myStr:String = myArr.join（" and "）;
trace（myArr）; //输出: one，two，three
trace（myStr）; //输出: one and two and three
[/sourcecode]
更多特性参见http://www.byywee.com/page/M0/S581/581497.html