When someone visits your web page, JavaScript will start the clock. When the leave that page, they will be alerted with the time they have been viewing the page! Cool!
The JavaScript Source: Page Details: Time on Page (OnUnload)
Simply click inside the window below, use your cursor to highlight the script, and copy (type Control-c or Apple-c) the script into a new file in your text editor (such as NotePad or SimpleText) and save (Control-s or Apple-s). The script is yours!
Page Details