JavaScript String search()

search() returns the index of the first match in a string. Its main strength is regular-expression searching. If no match is found, it returns -1.

const text = "Learn JavaScript";
console.log(text.search(/javascript/i)); // 6

search() Syntax and Return Value Top ↑

string.search(regexp)

If you pass a non-RegExp value, JavaScript converts it to a regular expression. The method returns the first matching index or -1.

Search Using Text Top ↑

const text = "Welcome to https://www.plus2net.com";
console.log(text.search("https://"));

For a plain literal search, indexOf() or includes() often communicates the intent more directly.

Search with a Regular Expression Top ↑

const text = "Order ID: AB-2048";
const position = text.search(/[A-Z]{2}-\d{4}/);
console.log(position);

Flags such as i make a pattern case-insensitive.

When search() Finds No Match Top ↑

const text = "JavaScript";
if (text.search(/python/i) === -1) {
  console.log("Not found");
}

search() vs indexOf() Top ↑

Both return the first matching index or -1. indexOf() is designed for literal strings and accepts a starting position. search() is designed around regular expressions and does not provide a start-position argument.

search() vs match() and matchAll() Top ↑

Use search() when you need only the first index. Use match() when you need match data. Use matchAll() with a global regular expression when you need all matches plus capture information.

Check Whether a URL Prefix Appears Top ↑

The original page checked whether https:// exists inside a string. A clearer modern version is:

const value = "Welcome to https://www.plus2net.com";
const position = value.search(/https:\/\//);

if (position === -1) {
  console.log("Not found");
} else {
  console.log(`Found at index ${position}`);
}

Once text is found, replace() can be used when the next task is substitution.

Common search() Mistakes Top ↑

• Expecting the matching text rather than its index.
• Forgetting to compare the result with -1.
• Expecting a second argument to set the starting position.
• Using an unescaped regular-expression pattern when the search text contains regex metacharacters.
• Using search() for a plain substring when includes() would be simpler.

← String Reference Lowercase Strings →

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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