The trim() function in PHP removes whitespace and other predefined characters from both sides of a string.Here's how it works in PHP 8, PHP 8.1, PHP 8.2, PHP 8.3 and PHP 8.4.Syntax

trim(string $string, string $characters = " \t\n\r\0\x0B"): string

Parameters$string: The input string$characters (optional): Specifies which characters to remove (default removes whitespace characters)

Common Whitespace Characters

" " - ordinary space"\t" - tab"\n" - new line"\r" - carriage return"\0" - NULL byte"\x0B" - vertical tabExamples1. Basic Usage (removing spaces)

$str = " Hello World! ";echo trim($str); // Outputs: "Hello World!"

2. Removing Specific Characters

$str = "Hello World!";echo trim($str, "Hed!"); // Outputs: "llo Worl"

3. Removing Multiple Types of Whitespace

$str = "\t\tHello World!\n\n";echo trim($str); // Outputs: "Hello World!"

4. Trimming Specific Characters from Both Ends

$str = "ABCHello World!CBA";echo trim($str, "ABC"); // Outputs: "Hello World!"

5. Real-world Example (form input)

$username = " user123 ";$clean_username = trim($username);// Now $clean_username is "user123" without spaces

Related Functions

ltrim() - Remove characters from the left side only.rtrim() - Remove characters from the right side only.The trim() function is particularly useful when processing user input from forms to remove accidental whitespace.