You may ask yourself, "Why would I use wigets?" I honestly couldn't have answered this a few months ago, before finding Dojo anyway. The answer is really quite simple once you see how widgets improve the functionality and appearance of your web applications, without taking a long time to implement.

Enhanced User Experience

Widgets "enhance the user experience". In layman's terms, that means that you can design web pages that are easier for people use, more quickly understandable, less error-prone, and flashier than web pages in plain html.

Easier to use - the Select widget for example, will narrow down the list of available choices based on keystrokes the user enters. That makes it faster to use than a normal HTML select box.

More quickly understandable - a web page with tabs will let the user easily navigate between different sections, and helps to make clear all the different sections of code that are on one page.

Less error prone - validation widgets will immediately notify users when they have entered an incorrect value, and/or automatically correct the value.

Flashier - dojo's menu code will fade in / out menus, or use some other effect, rather than a plain appear/disappear that you get with pure CSS menus

Faster Development

Widgets make it easy for web developers to add enhanced functionality. Here's why:

No Javascript Required

Web designers are generally very good with HTML. The really good ones are usually so involved in design that they don't even bother with learning the extra stuff that comes along with its dynamic aspect.

For these kinds of users, specifying widgets via HTML is a great solution. Not only is markup useful for being able to design with a placeholder element laying in wait, but many of the widgets actually analyze what they've laid out and use them as if properties were passed to the JavaScript object.

A great example of this is the tree widget. All that the designer has to do is lay out an HTML list, assign some attributes and they can have things going without having to touch a bit of code.

No worrying required

Widgets solve a bunch of issues (like cross-browser support) behind the scenes, so you don't have to worry it. See the next section for more detail about that.