The isset() function is an inbuilt function in PHP which is used to determine if the variable is declared and its value is not equal to NULL.
bool isset( mixed $var [, mixed $... ] )
Parameters: This function accept one or more parameter as mentioned above and described below:
- $var: It contains the variable which need to check.
- $…: It contains the list of other variables.
Return Value: It returns TRUE if var exists and its value not equal to NULL and FALSE otherwise.
Below examples illustrate the isset() function in PHP:
Value of variable is set Array is Empty
bool(true) bool(true) bool(true) bool(true) bool(false)