Link

Pattern: :target   Definition: The :target pseudo-class matches the target element. (A target element is an URI refers to a location within the document. It ends with a "number sign" (#) followed by an anchor identifier.).   Examples: Style an <h2> element that is the target element of the referring URI. h2:target { border: 2px dashed burlywood; }

Pattern: :visited   Definition: The :visited pseudo-class matches links that have already been visited by the user.   Examples: Style all visited links a:visited { color: tomato; }

Pattern: :link   Definition: The :link pseudo-class matches links that have not been visited.   Examples: Style all unvisited links a:link { color: royalblue; }

jQuery URLive lets you easily create a live preview of any url base on its Open Graph properties and other details, similar to Facebook's post attachment.  It doesn't only work on a <textarea> or <input> it also works on <a> tag and any element with a URL on its content. It's pretty lightweight as data fetching is done asynchronously via AJAX. It also doesn't require any back-end or PHP file to crawl and get the data as it uses YQL to query and make request on other domains.