PHP Filter_id Function
What is filter_id() in PHP?
filter_id() is a function, used to check and return the ID number for the specified filter from insecured sources. If the filter is available, it returns the ID. Else, It returns NULL.
In the above syntax, 'filter_name' is the name of the filter, to which ID number is to be retrieved.
In the above example, the ID number of the filter validate_url '273' is returned.