The StartTheTimer function starts by checking to see if the secs variable has counted down to zero yet. If it has, first it stops the clock. Then it checks to see if the form field has data in it. If the form field has data, submit the form. Otherwise, restart the clock.

If the time hasn't counted down to zero yet, subtract one from the counter, and set the function to execute again in one second. The function is recursive, calling itself. Load the page, and the timer waits, checking to see if something had been entered. Once it has, it submits the form, which does some further processing.

To start the ball rolling, you need to execute the InitializeTimer function, like this:

InitializeTimer();

As long as that is somewhere on the page, you're all set.

This example is a bit more simplified than what actually went into production (obviously since we didn't create a processing page). I did some Ajax-y stuff with iFrames to show a running status of what attendance was entered and when. Errors were also shown in the status list without interrupting future scans. It worked out well.

Friday: Graphing Types
I was sitting with a client discussing a report. He wanted to view the report information in a graphical format, so we had decided to implement this report using cfchart. I made the mistake of asking if he would prefer a bar chart or a pie chart. The client, being like normal clients, asked if I could do both. It turns out I could.

There are three tags that are used to generate charts in ColdFusion: cfchart, cfchartseries, and cfchartdata. Cfchart defines overall attributes for graph, such as the format (PNG, JPG, or Flash), height, width, and other display attributes that affect the full chart. Full information is at the livedocs at http://livedocs.macromedia.com/coldfusion/7/htmldocs/00000226.htm#2619630. cfchartseries is used to define the chart style, such as bar or pie. There are eleven different types of charts supported. Full documentation on the tag is at http://livedocs.macromedia.com/coldfusion/7/htmldocs/00000228.htm#2741830. You can have multiple chart series inside a chart, but this tag must be nested inside a cfchart. cfchartdata is used to define a single point on the graph, and it is the simplest of the three tags, as it only defines the name of the point and its value. Cfchartdata must be located inside a cfchartseries. Its full documentation is located here: http://livedocs.macromedia.com/coldfusion/7/htmldocs/00000228.htm#2741830.

I didn't want to have to build multiple versions of the same report, one with a bar chart and one with a pie chart. I decided to pass the chart type as a URL variable into the template, and use that to decide what type of chart to display. This gives me the option of easily adding any of the 11 types supported by cfchart when the client asks for more in the future.

First I cfparamed a charttype variable to default it:

<cfparam name="chartType" default="pie">

That should cover me in the case of nothing being passed in. The next step was to get the data. I decided to use a query. In this example, I'll pull from my MyFriend's RSS Aggregator database and display the number of items for each RSS Feed:

<cfquery name="getTotals" datasource="#request.dsn#">
   select RSSFeeds.title, count(Items.ItemID) as total
   from RSSFeeds join items on (RSSFeeds.RSSFeedID = Items.RSSFeedID)
   group by RSSFeeds.title
</cfquery>

And finally the page can display the chart like this:

<cfchart format="flash">
   <cfchartseries itemcolumn="title" valuecolumn="total" query="getTotals" type="#chartType#" />
</cfchart>

Since the chart is getting data from a query, the cfchartdata tag is not needed. The cfchart, simply enough, tells us that we're creating a flash chart. I can load the page using URLs like this:

ChartTest.cfm?chartType=pie
ChartTest.cfm?chartType=bar
ChartTest.cfm?chartType=line

( and so on)

It was a simple, elegant solution that gave me another happy client.

Conclusion
It was a good week. I love dealing with ColdFusion as a language because of the way it makes complicated development tasks seem simple. I feel confident knowing that it will help me address the next "crazy" idea. What are your favorite "odd" requests you've had to deal with? How did you solve them? Just fill out the contact form on my blog (www.jeffryhouser.com) and let me know!