Working with Undefined in JavaScript

There are times when an application has to admit that it has reached a dead end. This will allow developers to focus on specific parts of the application that will be helpful to users. With this ability, users will use only access the powerful functions instead of exploiting the application for flaws.

Creating an end in a function can be done with “undefined”. In gist, undefined is a value that can be placed in the application so that the function will stop or the parameters will cease to be implemented. Undefined will allow developers add customization for users as well as focus on essential functions.

There are two forms of definition for undefined in JavaScript and Ajax. The first version defines the value as a variable that's not recognized or has been adapted for use in the application. Since it's undeclared, it cannot have significant effects in the application but will limited variables. The second definition, the one ECMA recognizes, defines the value as declared variable. However, the actual value of undefined was never implemented. In this definition, undefined can be part of the application but provides an end to the function.

Primitive Value to Variables

Even though undefined may seem like an unimportant value, it's highly adaptable and can be used in many ways. As already indicated, undefined can be used as a value which means it will be treated as part of the data. However, undefined can also be used as a variable. Instead of simply being a data for users; undefined became a tool for various functions.

But there is a limitation. Browsers will dictate on how the undefined can be used. IE do not recognize undefined when the function is implemented as a variable. This means developers have to be cautious in implementing undefined as variables since it might not work with most users.

Implementing as TypeOf

Another function developers can expect from undefined is its implementation along with TypeOf function. This is expected since developers can use undefined in order to set additional parameters. TypeOf is not just another function but a strong parameter that can be used to properly screen the needed data.

Tips in Implementing Undefined

• Don't just force undefined in the application - creating an undefined in the application is not just because you run out of options. Carefully plan the implementation of undefined so that the function will work with the application and not against it.

• Avoid unnecessary use of undefined - as already indicated, developers can simply push the use of undefined. This means developers can push for more functions in the application and not just use undefined when nothing works. While it will not affect the speed of the application, it will certainly increase lines.

• Avoid variables - IE is still the most popular web browser. Developers do not have to push for undefined as variables since there are other options. Extra coding to trick IE is just not worth it. Focus on value so that undefined will work well for many users.