Getting ad banners to load last 
By Don Lancaster                                                                     
Version 1.1 June 25, 1997
Copyright c. 1997 by Don Lancaster and Synergetics, Box 809, Thatcher AZ, 85552
(520) 428-4073. synergetics@tinaja.com All commercial rights and all electronic media
rights are *fully* reserved. Linking welcome. Reposting is expressly forbidden.

Further support on www.tinaja.com  


There is nothing more infuriating than having to sit around and wait for an ad banner or
some other obnoxious header to completely download before a page can be attractively
viewed. Since a bored or a frustrated viewer is a gone viewer, here are some ploys to
control what loads when on an HTML page...

(1) -- Keep banner file sizes short

The longer the banner and the more there are of them, the longer it takes to display. Always
keep banners few and small. Use a minimum number of colors and optimize GIF files for
small palettes, no comments, and no trailers. Avoid ~all~ banner animation ion, sound, or
other special effects.

The GIF Construction set sharewave includes several file length optimizing tools. A
reasonable goal for a 65 x 280 pixel banner is 5500 bytes or less.

(2) -- Use the LOWSRC operator

The LOWSRC operator in HTML lets you initially display one image and then later display
a second one. The second image starts displaying after all currently viewable information is
placed on screen. Normally, LOWSRC is used to provide a faster loading lower resolution
"placemarking" graphic image. It also can be used for a two-step animation effect.

But downloading yet another banner file can end up adding insult to injury. So one ploy I
use is to Let LOWSRC rewrite your background wallpaper. This defers writing the real
banner until after loading, but has zero penalty in the total number of bytes that need downloaded
before a useful page gets displayed.

(3) -- Use the 1 x 1 preimage ploy

Certain browsers do not bother to initially image anything that is far enough downscreen that it
cannot be seen without scrolling. Only after scrolling do the needed display elements appear.

Which leads to the following subtle annoyance: You view a page and decide to scroll down
before the banners are fully displayed. Any new design elements in the downscreen info are
not yet present and will not fully display until after the (now invisible) banners finish themselves.
So your downscreen info still might not be viewable.

Since HTML images anything in the file order received, I've found this trick to be a useful
workaround: Place anything you want your viewer to see ahead of a full banner load earlier
in your file and ask it to create a 1 x 1 single pixel image.

Here is the sequence: Needed page elements go down first, creating some negligble dots in
the upper left of the first screen. The banner lowsrc substitute goes down next, preferably
using a file (such as wallpaper) that is needed anyway. The rest of the viewable page follows.
The banners then try to load and invisibly continually downloading on a scrolldown.

On a scrolldown, the needed elements have already been downloaded, so they do not have to
wait for the banners to finish. The illusion is a ready to view page, even though the banners are
continuing to download in the background.

An example...

Here's an example from my home page. Start with the usual stuff, including wallpaper...

A group of blue buttons will be needed downscreen. Download one of these now as a 1x1
pixel image. The button will be available for downscreen use ahead of any full banner loads.
A single dark pixel will appear ahead of the first banner...

Now put down the banners, substituting the existing wallpaper for their initial low res images...

Here is what happens: A single pixel gets written to the screen. The banner space gets cleared
back to the background. All needed viewable screen elements go down. The banner then starts
its slow display sequence, but the viewer has all the rest of the viewable page ready to go.

Should the viewer scroll downscreen, the needed buttons are already downloaded so a full
downscreen image will rapidly appear. The still incomplete banners will quietly download as
a background task.

As a bonus, there's an "element of mystery" of what the banner is really going to end up
saying. But one that is in no way forced upon the viewer.


Copyright c. 1997 by Don Lancaster and Synergetics, Box 809, Thatcher AZ, 85552
(520) 428-4073. synergetics@tinaja.com All commercial rights and all electronic media
rights are *fully* reserved. Linking welcome. Reposting is expressly forbidden.
Further support on http://www.tinaja.com
Consulting services available via don@tinaja.com