//字符串的Iterator函数
//例子:
//var it=new StringIterator("a,b,c,d",",");
//while(it.hasNext()){
//  alert(it.next());
//}
 1function StringIterator(aStr,aSep){
 2  this.origin=aStr;
 3  this.sep=aSep;
 4  this.remain=aStr;
 5  this.nextStr=null;
 6  this.hasNext=hasNext;
 7  function hasNext() {
 8   var iIndex=0;
 9   if(this.remain==null){this.remain='';}
10   if(this.remain==''){
11     this.nextStr=null;
12     return false;
13   }
14   iIndex=this.remain.indexOf(aSep);
15   if(iIndex<0){
16     this.nextStr=this.remain;
17     this.remain='';
18   }else{
19     this.nextStr=this.remain.substring(0,iIndex);
20     this.remain=this.remain.substring(iIndex+this.sep.length);
21   }
22   return true;
23  }
24  this.next=next;
25  function next() {
26   var strRtn=this.nextStr;
27   this.nextStr=null;
28   return strRtn;
29  }
30}
31