Sanitization
filter_has_var
Filter
PHP Manual

# Filter Functions

## Table of Contents

- filter_has_var — Checks if variable of specified type exists
- filter_id — Returns the filter ID belonging to a named filter
- filter_input_array — Gets external variables and optionally filters them
- filter_input — Gets a specific external variable by name and optionally filters it
- filter_list — Returns a list of all supported filters
- filter_var_array — Gets multiple variables and optionally filters them
- filter_var — Filters a variable with a specified filter

Sanitization
filter_has_var
Filter
PHP Manual