void DoMaxD(int sock, PCSTR url)
{
  GraphData gd;
  SizeData sd;
  GetData(&gd,&sd,url);
  char buffer[20];
  sprintf(buffer,"%d",gd.MaxD);
  writestring(sock,buffer);
}
Listing 3—The DoMaxD function is called when the HTML code contains a comment of the form. <!--FUNCTIONCALL DoMaxD-->. This mechanism is used to put dynamic content into an otherwise static web page.