How to escape special characters in PHP?

The PHP function addslashes() is used to escape special characters from a string. The function automatically adds a backslash before each of the following characters:

• single quote ( ' )
• double quote ( " )
• backslash ( \ )
• the NUL character

For example:

$string = 'He says "John".';
$string = addslashes ($string);

// Displays: He says \"John\".
echo $string;

See also:

• How to escape HTML tags from a string in PHP?