String.replace() Replace a substring
Last updated: 2026-09-09
String.replace() Replace a substring
replace swaps matched text; a string pattern replaces only the first match, a regex with g flag replaces all.
| Category | Strings |
|---|---|
| ES version | ES1 |
📝 Syntax
const newStr = str.replace(pattern, replacement);⚙️ Parameters
| pattern | A string (first match only) or regex (g flag for all). |
|---|---|
| replacement | Replacement string or callback. |
Returns：A new string with replacements; the original is untouched.
Mutates the original：No (returns a new value)
▶ Example
Edit the code, press Run, and see the result in the output panel:
Output：
orange apple apple
orange orange orange
price 200 total 600⚠️ Warning A string pattern replaces only the first match — use /pattern/g or replaceAll().
💡 Tip Callbacks enable computed replacements.
🌐 Browser support
| Browser |  Chrome |
 Edge |
 Firefox |
 Safari |
 Opera |
|---|---|---|---|---|---|
| String.replace() | ✓ v1 | ✓ v12 | ✓ v1 | ✓ v1 | ✓ v1 |
| Supported by all modern browsers | |||||
🏷️ Related Items
💡 Related Cases
More case studies coming soon — check back later.
📚 Related Tutorials
❓ FAQ
QHow to replace all matches?
AThree ways: regex g flag, replaceAll() (ES2021), or split+join.
QWhat are the callback parameters?
AFirst arg is the match, then capture groups, then offset and the original string.
QDoes replace mutate the original?
ANo — strings are immutable; assign the result.
