Basic HTML defines the components of a Web page so the browser can display them. It was never meant to handle animations or interactivity, yet those are just the features that many Internet users now expect.
Dynamic effects range from simple popup windows to elaborate animations and special effects.
You have to understand the basics before you ever even consider making your plain HTML dynamic. They define the font, color, size, and display attributes of elements on the page. JavaScript creates effects by accessing the components of the DOM and changing them on the Web page. This increases your site's usability level. Both Netscape and Explorer have promised to adhere to those standards once they are final.