What is the use of isset function in php?

Answer 1

Its not only works with var to check if they are not empty and save errors, its also works with forms.
if isset($_POST[fieldname])
//send to database
else
echo 'enter fieldname';

Answer 2

You'll find the best answer over here:
http://php.net/manual/de/function.isset.php

Answer 3

it returns a boolean value (TRUE or FALSE) based on the parameter given. This way you can check if (in example) a variable is actually set or not.

Answer 4

It is used for pressing the button to do some specific functions calling by functions like.
if isset($_POST['sing_up']){
echo "Thank you for Signup";
}

Answer 5

hz