Javascript was originally developed by Netscape and is supported by most browsers. The majority of Internet users use Microsoft's Internet Explorer as their main browser and has Javascript enabled. Some users may disable Javascript to block popup ads, but browsers have now added popup blockers, so users no longer need to disable Javascript.

Javascript can be used to validate form information, before sending the information to a database. This is useful to be certain that visitors fill in all required form fields (boxes of information). Javascript can be used for drop-down menus, real-time clock displays, mouseover effects and much more.