Javascript Data Type undefined

Description

Click the following links for the tutorial for Data Type and undefined.

1. Test if a variable is undefined, whether the variables have been assigned a value or not
2. Use global variable with undefined value
3. Check if undefined with typeof
4. Check Type of undefined
5. Assign undefined to a variable
6. Use if statement to check undefined values
7. Clear and remove undefined values from an array
8. Put a variable check inside a string



9. Check availability of a variable