上海javascript的面试题

<script>
String.prototype.in=function(a,b,c,d){
if(a==this.valueOf()||b==this.valueOf()||c==this.valueOf()||d==this.valueOf()){
return true;
}else{
return false;
}
}
String.prototype.in=function(a,b){
if(a==this.valueOf()||b==this.valueOf()){
return true;
}else{
return false;
}
}
var a="2";
alert(a.in("2","3"));
</script>