A program or application that will work on any peripheral devices within a certain protocol is considered device independent.
Dialing a telephone number is a simple example of a device-independent action. All telephones operate under the same protocol. No matter what brand of telephone you use, you can always phone home. Device independence ensures that all internet-enabled devices — everything from your games console to a Web-surfing clock radio — will be able to communicate with each other in the future.
Events are user interactions with their computer, such as a mouse click or key press.
In the good ol’ days, computers handled user interactions as input of batched data. The user fed a hunk of data in, the computer did something to that data, then produced the results. With the advent of interactive devices like the GUI interface, computers could display answers to computations onscreen. The input for these interactions are events caused by the user, which could be keystrokes, button clicks, or the position of the mouse pointer.
(see Event Handler).
Event handlers are functions that handle client-side events.
Short for “inline frame,” Iframes are used to insert a block of text into a separate HTML document. Iframes can float above page elements using absolute positioning, or they can be placed directly on the page with page elements flowing around them. Unlike regular frames, Iframes can not be resized by the user. (NOTE:Iframes are not supported by older browsers.)
Image maps are images that have several links geographically mapped onto it.
For example, an image map of a photograph of the Beatles might enable you to click on Ringo and receive a page describing his drumming abilities. Click on George, and receive a file about how Eric Clapton stole Patti Boyd. One thing to remember about image maps is that they are a purely visual form of navigation, so if your visitor isn’t loading the images, they’ll never know where to click. For this reason, you should always include text links under the images as an alternative way to navigate.