The Preferences dialog lets you choose how the clocks behave within the program itself. You can have them running continuously in real time or in static mode where you have to click on the clock to update the time.
The output preferences affect the formatting of the HTML, CSS and JavaScript generated. Web browsers generally don’t care about return/line feed characters at the end of each line but some editors do. The correct format for your system is chosen automatically but you might want another. Choose from Windows, Macintosh or UNIX line endings.
A word of caution. As mentioned earlier, using timers on Web pages can be demanding on slower processors. If you have multiple browser windows open with clocks running in each one, it can make the browser seize-up and you will have to force-quit the browser and relaunch it. This is not very likely to happen in real life browsing situations but can happen while building the page initially. Avoid opening a clock in more than one browser window at a time.
Whilst dynamic CSS techniques work fine in modern browsers, older browsers may give unsatisfactory results or not work at all. You should consider making alternative provisions for people who use legacy browsers.