1. This is the first paragraph. By taking advantage of cascading style sheets, you can assign unique IDs to all sorts of document elements: not just paragraphs, but headings, lists, styles - virtually any document element. And once you have a unique ID assigned to a document element, you can display or hide that document element using a coding technique similar to the one shown here.
2. This is the second paragraph.
3. This is the third paragraph. You can dynamically change the content this paragraph contains by entering your own text in the form field below.