String String Object
Last updated: 2026-09-09
String String Object
String is JavaScript's built-in string object with 30+ methods for searching, slicing, replacing and case conversion. Strings are immutable.
| Category | Strings |
|---|---|
| ES version | ES1 |
📝 Syntax
const str = "Hello"; // literal (preferred)
str.length; // 5▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
12
HELLO, WORLD
true⚠️ Warning Strings are immutable — every method returns a new string.
💡 Tip Template literals are the modern way to build strings.
🏷️ Related Items
💡 Related Cases
More case studies coming soon — check back later.
📚 Related Tutorials
❓ FAQ
QWhy are strings immutable?
AImmutability lets engines share and cache strings safely.
QHow to iterate each character?
Afor (const char of str) handles surrogate pairs correctly.
QStrings vs character arrays?
AJS strings are immutable UTF-16 sequences, not arrays. Use split('') to convert.
