validate variable before use in function

validate variable before use in function

References

Reference NO 1

http://stackoverflow.com/questions/15197240/validate-variable-before-use-in-function

Reference NO 2

http://stackoverflow.com/questions/15522440/validate-post-variables-for-functions-that-use-them

Reference NO 3

http://www.phpro.org/tutorials/Validating-User-Input.html

Reference NO 4

http://php.net/manual/en/function.empty.php

Reference NO 5

http://php.net/manual/en/function.isset.php

Reference NO 6

http://www.sitepoint.com/input-validation-using-filter-functions/

Reference NO 7

http://www.w3schools.com/php/php_filter.asp

Reference NO 8

http://coredogs.com/lesson/form-and-php-validation-one-page