Problem Statement
What's the difference between ordered and unordered lists?
Explanation
Ordered and unordered lists are two fundamental types of lists in HTML, each serving different purposes based on whether sequence matters. An ordered list, created with the ol tag, displays items with numbers, letters, or Roman numerals. The numbering indicates sequence and order. Ordered lists are used when the order of items is important or meaningful. Common use cases include step-by-step instructions where each step must be followed in order, recipes with sequential cooking steps, rankings or top ten lists where position matters, procedures or processes that have a specific order, numbered terms and conditions, and tutorial steps that build on each other. The ol tag automatically numbers items starting from 1 by default. You can customize the numbering style using the type attribute to show uppercase letters, lowercase letters, Roman numerals, or numbers. You can also use the start attribute to begin numbering from any number, and the reversed attribute to count down instead of up. An unordered list, created with the ul tag, displays items with bullet points. The bullets indicate that the items are related but their order does not matter. Unordered lists are used when items are equal in importance and sequence is not relevant. Common use cases include lists of features where no feature is more important than others, shopping or ingredient lists where you can gather items in any order, navigation menus where links are equally accessible, lists of team members or employees, collections of related links, and sets of options or choices. The ul tag displays circular bullets by default, but you can change the bullet style using CSS. The key difference is semantic meaning. Using ol tells users and search engines that order matters. Using ul indicates that items are related but interchangeable in order. Choosing the correct list type improves the semantic quality of your HTML and helps with accessibility. Screen readers may announce items differently for ordered versus unordered lists. Both list types use the li tag for individual items. You can nest ordered lists inside unordered lists and vice versa to create complex hierarchical structures. Both are block-level elements that start on new lines. Understanding when to use each type shows good knowledge of semantic HTML and is commonly asked in web development interviews. In practice, if you are unsure which to use, ask yourself: does the order matter? If yes, use ol. If no, use ul.