fetch related tags in different days of del.icio.us

For my study, I just write a small PHP program, which shows the relation of a specific tag in different days.

the php file could be download from here 

The return format is as follow
<data name="Queried Tag" >
   <date time="
YYYYMMDD" total="number of tag at that date">
      <tag name="
related tag" count="number of co-occurence"/>

Actually it directly parse the info on the del.icio.us page.
To avoid being banned by del.icio.us, the program would sleep 1 second for each 10 pages.

I would also think of adding the count of the related tag of a specific day. However, instead of really go through  all pages until find the day, I have no good idea of fetching those information. 

If any of you have a better solution, please help me, Thanks!!!!

Thanks for the HTML parser written by S.C.Chen.
For more detailed info, please visited the SourceForge
Also, there's a simple chinese tutorial over here