[Javascript] Banner Ad scripts

[Paul Novitski]

Tim,

Allergic as I am to advertising, how loathe I am to aid in its 
proliferation!  However, the basic technology can be used for Good as well 
as Evil; I leave the choice to you, O Grasshopper.

In addition to what Håkan says generally about the process, I would add 
only a few comments on two possible approaches:

1) When the page is rendered, a single item (image & link) appears and 
remains fixed for the life of the page.  Each time the page is revisited, 
the item changes randomly or in rotation.

2) The page contains an item that changes every N seconds, either randomly 
or in rotation.

Approach 1) can be handled either server-side or client-side by selecting 
from a list of optional items when the page is built.  Approach 2) is best 
done client-side to avoid a superabundance of network traffic.

I would group the options in an array.  Rotating in sequence means keeping 
a record of the last element selected, say either in the visitor's cookie 
(to create a per-user rotation) or in a master file on the server (for a 
site-wide rotation).

You probably know how to select randomly from a list; the approach I 
generally use is to multiply the number of items in the list by a random 
number (that being a value between 0 and 1) and take the closest integer of 
the result.  One caveat: the usual random numbers we see never equal zero 
or one but merely approach them, and you want to make sure you include the 
first & last items in the list.  Because we know that the Javascript array 
begins indexing with zero and ends with length-1, we can use the Javascript 
function Math.floor() that neatly returns the integer less than or equal to 
the input value:

         var iItem = Math.floor(Math.random() * aItems.length);
         DoSomething(aItems[iItem]);

Then of course you can use array values to set the src property for an 
image and the href & title properties for an anchor tag.

Paul


At 05:12 AM 3/17/2004, you wrote:
>Does anyone have any advice for good banner-advert cyling scripts -
>basically, I want to set up a rotating series of banner ads on a new
>website, but haven't done this before. Any comments, or recommendations ?
>
>Tim in Ireland.
>
>
>PS Happy St.Patricks Day !!!
>
>_______________________________________________
>Javascript mailing list
>Javascript at LaTech.edu
>https://lists.LaTech.edu/mailman/listinfo/javascript