JavaScript RegExp Form Feed Metacharacter (\f)

What Is \f?

\f matches the form feed control character (U+000C, ASCII 12). It once meant “next page” on printers and still shows up as a page or section break in some legacy text files.

\f  → form feed (U+000C)
\n  → newline (different character)
\r  → carriage return (different character)
\s  → any whitespace, including \f

"page1\fpage2"  → string with a form feed
/\f/.test(...)  → true when FF is present
split(/\f/)     → break on page markers

How to Use \f

Treat form feed as a specific control character — detect it, split on it, or replace it.

1. Build or import text that may contain form feeds (string escape: "\f").
2. Use /\f/ with test, match, split, or replace.
3. Add the g flag when you need every form feed, not just the first.
4. Do not confuse \f with \n — they are different characters.

Pseudocode

pattern has "\f"
read next character ch from the string

if ch.codePoint === 0x000C:   // form feed
    accept match
else:
    fail this path

common actions:
  test(str)      → true/false
  split(str)     → parts between FF
  replace(str)   → swap FF for space or "\n"

Cheat Sheet

Keep these facts handy when cleaning control characters.

Live Preview

Run common \f operations on sample text that contains a form feed.

text = "Page A\fPage B"
/\f/.test(text)
→ true

/* form feed (U+000C) is present */

JavaScript Examples

Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.

const withFF = "section\fnext";
const plain = "section next";

console.log(/\f/.test(withFF));  // true
console.log(/\f/.test(plain));   // false
console.log(/\n/.test(withFF));  // false

true
false
false

const doc = "Title\fChapter 1\fChapter 2\fIndex";

const sections = doc.split(/\f/);
console.log(sections);
// ["Title", "Chapter 1", "Chapter 2", "Index"]

console.log(sections.length); // 4

["Title", "Chapter 1", "Chapter 2", "Index"]
4

const legacy = "Page A\fPage B\fPage C";

const readable = legacy.replace(/\f/g, "\n\n");
console.log(JSON.stringify(readable));
// "Page A\n\nPage B\n\nPage C"

"Page A\n\nPage B\n\nPage C"

Performance Notes

Matching a single control character is cheap. Prefer /\f/ when you only care about form feed; use \s only when any whitespace should match.

Key Takeaways