Statisticus, Why and How?
Part IV - Adding More Fields
by Pascal Hagen
4. Adding More Fields
By adding some more fields to our table, we will get some more statistics such as
mostly used screen resolutions and color depths. It is very valuable piece of
information. How do you feel about being stuck with that 216-safe color palette?
Should you stay within safe palette or your visitors run in high color mode with
more than 800x600 resolution? Well, here's how to learn:
Client-side scripting gives you the ability to directly talk to the browser and ask
about the environment. We will use JavaScript to do that.
<![CDATA[
<script language="JavaScript" type="text/javascript">
<!--
f = "" + escape(document.referrer);
v = navigator.appName;
if (v=='Netscape')
{b = 'NS';}
if (v=='Microsoft Internet Explorer')
{b = 'MSIE';}
if (navigator.appVersion.indexOf('MSIE 3')>0)
{b = 'MSIE';}
u = "" + escape(document.URL);
w = screen.width;
h = screen.height;
if (v != "Netscape")
{c=screen.colorDepth;}
else
{c=screen.pixelDepth;}
info= "w=" + w + "&h=" + h + "&c=" + c + "&r=
" + f + "&u="+ u + "&b=" + b
document.write("<img src=\"/count.asp?" + info + "\">");
-->
</script>
]]>
What we actually do here is a little bit tricky, we call an asp page externally!
We tell the browser that our asp page (count.asp) is an image. We will do what
we say to the browser, but first we will have a look at the information
we are sending to count.asp.
Our count.asp file, which is responsible for storing the data to the table needs to
catch the following variables;
w: screen width
h: screen height
c: color depth (in bits)
r: referer
u: url of the page
b: browser brand
We had used Request.Servervariables("script_name") before, why sending URL again? Answer
is simple, script_name will always return count.asp because we are making a tricky external
call to it. This is why we should send the url.
Now, in count.asp, it's easy to store the variables into the table.
After running such a counter for a long time, you'll see that the database size grows and
grows. What should we do? We don't want to give up our new fields, but we need to somehow
use less bytes. A kind of compression? No, it's called data normalization.
Part I - Introduction
Part II - Measurement Tools
Part III - Simple Statistics
Part IV - Adding More Fields
Part V - Data Normalization
Part VI - Data Gets Valuable
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