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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.  

jQuery.localScroll will animate a regular anchor navigation. It will allow your visitors to navigate your site with a smooth scrolling effect.   Each time a link is clicked, the element you decide(can be the whole screen), will gradually scroll to the targeted element, instead of "jumping" as it'd normally do.  

Square Menu creates a square-like menu animation for website using jQuery and CSS3.  

Scroll To provides a simple way to animate to anchors. Scrolling to a spot in an HTML page is pretty simple to do with JQuery, but if you have a lot of IDs on the page to scroll to, the code can get a little messy. This plugin solves that by allowing you to write your anchor tags just as you normally would with the href attribute pointed at the ID you would like to move to (e.g. href="#importantSection".) This means that if JavaScript is turned off, your site will continue to function normally.