Animations are seen in many web sites throughout the Internet. Ease of use is considered as a possible reason for the growing use such multimedia feature in designing of web sites. While animations are ubiquitous in the Web environment, there is an inadequate understanding of its effect on user's attention. Animations are advantages of information technology for web designers, but important questions remain about whether animations work in all situations and for all users. Focusing on web animation, this paper reviews literature and at the end it extracts guide lines for better designing of websites.