split()将一个字符串按照某个字符拆分为数组
join()将数组中所有原有元素按照某个字符连接成一个字符串
function fun_split(){var str="Apple,Microsoft,SamSung"
var items=str.split(",")
for(var i=0i<=items.lengthi++){
document.write(items[i]+"<br>")
}
}
function fun_join(){
var items=new Array("tom","jerry","alex","lucy")
var str=items.join("_")
document.write(str)
}