What is the best web technique for building a "count up" clock on my web site?

javascript

Flash is going away, I would not use it for a new project.

I’ve seen some interesting CSS clocks, for example,
http://joncom.be/code/css-clocks/

If it is just going to count up the years wouldn’t it be better to just update the HTML every year?

The main value you want is the interval between the starting of the business and when the page is being loaded. You will need to use Date-Time calculations to do it. Javascript can backdate using the Date() function. So It can be done through Client Side Javascript programming. It can also be done through Server-Side programming if you can access Php.

It becomes your choice, depending on whether your CMS will allow you to integrate your own JS smoothly.

@WyCnet PHP wouldn’t be an option for a dotnetnuke site

I changed my mind and agree with @johnpowell, just do it in HTML and update it once a year.

I would prefer to do it that way, it would certainly be easier. But my boss wants seconds, minutes, hours, days, months, years… I found a jQuery script for this, but it will need some work. Not exactly my area of specialty.

There is this.

http://praveenlobo.com/techblog/javascript-countup-timer/

I wouldn’t really bother with jQuery for this unless it is used elsewhere in the site.