What is the purpose of the trim function in PHP?

The trim function in PHP is used to remove leading and trailing whitespace characters from a string, including spaces, tabs, and newline characters.

Its functions include:

1. Remove any leading white spaces from the string.
2. Remove any trailing whitespace characters from the string.
3. Remove any whitespace characters at the beginning and end of the string.

This function is commonly used to process user input strings, removing any extra spaces or line breaks that may have been added by the user, as well as removing any whitespace characters from strings retrieved from databases or files.