The for-in loop doesn't work in ASP JavaScript the way it is "suppose" to. In Visual Basic, the for-in loop enumerates the members of a collection.

For Each item In the collection document.write item Next. Many JavaScript users mistakenly assume that the JavaScript for-in loop does the same thing. It does not -- the JavaScript for-in loop enumerates the members of a JavaScript object:

var obj = new Object();
obj.foo = 1;
obj.bar = 2;

// the following "for-in" writes "foo = 1 bar = 2
for (member in obj) document.write(member + "=" + obj[member] + " ");

To enumerate the items in a collection, use the Enumerator object:

var myEnum = new Enumerator(myCollection);

for (myEnum; !myEnum.atEnd() ; myEnum.moveNext() )
     document.write(myEnum.item());
}

myCollection can be for example:

• Request.Cookies
• Request.Form
• Request.QueryString
• Request.ServerVariables
• etc...

Enumerator objects are considerably more flexible than for-each-in loops.

Several enumerators can be declared at the same time for each collection, enumerators can be passed around as data, they can be reset to the beginning at any time, etc.

Description

Provides a way to enumerate items in a collection.

Syntax

new Enumerator(collection)

The collection argument is any collection object.

Remarks

Collections differ from arrays in that the members of a collection are not directly accessible. Instead of using indices, as you would with arrays, you can only move the current item pointer to the first or next element of a collection.

The Enumerator object provides a way to access any member of a collection and behaves similarly to the For...Each statement in VBscript, which repeats a group of statements for each element in an array or collection.

For Each element In group
    [statements]
    [Exit For]
    [statements]
Next [element]

array

A set of sequentially indexed elements having the same type of data. Each element of an array has a unique identifying index number. Changes made to one element of an array do not affect the other elements.

 

collection

An object that contains a set of related objects. An object's position in the collection can change whenever a change occurs in the collection; therefore, the position of any specific object in the collection may vary.