The primary use of the PHP filter is to validate the data coming from different sources.
- User input from a form
- Cookies
- Web services data
- Server variables
- Database query results
Filtering is an important feature for a web application to validate and sanitize the data coming from insecure sources. PHP supports the following filter functions.
- <filter_has_var()>
- Check if a variable of a specified input type exists.
- <filter_id()>
- Returns the ID number of a specified filter.
- <filter_var_array()>
- Get multiple variables and filter them.
- <filter input()>
- Get input from outside the script and filter it.
- <filter_input_array>
- Get multiple inputs from outside the script and filter them.
- <filter_list()>
- Returns an array of all filters it supports.
- <filter_var()>
- Get a variable and filter it.
