String.prototype.startsWith()

The startsWith() method of {{jsxref("String")}} values determines whether this string begins with the characters of a specified string, returning true or false as appropriate.

{{InteractiveExample("JavaScript Demo: String.prototype.startsWith()")}}

```js interactive-example const str = "Saturday night plans";

console.log(str.startsWith("Sat")); // Expected output: true

console.log(str.startsWith("Sat", 3)); // Expected output: false

## Syntax

```js-nolint
startsWith(searchString)
startsWith(searchString, position)

Parameters#

• searchString
• : The characters to be searched for at the start of this string. Cannot be a regex. All values that are not regexes are coerced to strings, so omitting it or passing undefined causes startsWith() to search for the string "undefined", which is rarely what you want.
• position {{optional_inline}}
• : The start position at which searchString is expected to be found (the index of searchString's first character). Defaults to 0.

Return value#

true if the given characters are found at the beginning of the string, including when searchString is an empty string; otherwise, false.

Exceptions#

• {{jsxref("TypeError")}}
• : Thrown if searchString is a regex.

Description#

This method lets you determine whether or not a string begins with another string. This method is case-sensitive.

Examples#

Using startsWith()#

const str = "To be, or not to be, that is the question.";

console.log(str.startsWith("To be")); // true
console.log(str.startsWith("not to be")); // false
console.log(str.startsWith("not to be", 10)); // true

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• Polyfill of String.prototype.startsWith in core-js
• es-shims polyfill of String.prototype.startsWith
• {{jsxref("String.prototype.endsWith()")}}
• {{jsxref("String.prototype.includes()")}}
• {{jsxref("String.prototype.indexOf()")}}
• {{jsxref("String.prototype.lastIndexOf()")}}