<!DOCTYPE html>
<html>
<body>
<?php
$str = "This Is Text";
echo "All T (uppercase only) Characters <br>";
echo addcslashes($str, "T") . "<br>";
echo "All Characters from A to Z (uppercase only) <br>";
echo addcslashes($str, "A..Z") . "<br>";
echo "All Characters from a to z (lowercase only) <br>";
echo addcslashes($str, "a..z") . "<br>";
echo "All Characters from A to z (uppercase and lowecase) <br>";
echo addcslashes($str, "A..z") . "<br>";
?>
</body>
</html>
OUTPUT
All T (uppercase only) Characters
\This Is \Text
All Characters from A to Z (uppercase only)
\This \Is \Text
All Characters from a to z (lowercase only)
T\h\i\s I\s T\e\x\t
All Characters from A to z (uppercase and lowecase)
\T\h\i\s \I\s \T\e\x\t