w3resource

JavaScript: Test whether a string starts with a specified string

JavaScript String: Exercise-46 with Solution

Write a JavaScript function to test whether a string starts with a specified string.

Test Data:
console.log(startsWith('js string exercises', 'js'));
true

Pictorial Presentation:

JavaScript: Test whether a string starts with a specified string

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to test whether a string starts with a specified string</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function startsWith(input, string) {
  return input.indexOf(string) === 0;
}
console.log(startsWith('js string exercises', 'js'));

Sample Output:

true

Flowchart:

Flowchart: JavaScript: Test whether a string starts with a specified string

Live Demo:

See the Pen JavaScript Test whether a string starts with a specified string-string-ex-46 by w3resource (@w3resource) on CodePen.


Improve this sample solution and post your code through Disqus

Previous: Write a JavaScript function to get humanized number with the correct suffix such as 1st, 2nd, 3rd or 4th.
Next: Write a JavaScript function to test whether a string ends with a specified string.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



JavaScript: Tips of the Day

How to check whether a string contains a substring in JavaScript?

ECMAScript 6 introduced String.prototype.includes:

const string = "foo";
const substring = "oo";

console.log(string.includes(substring));

includes doesn't have Internet Explorer support, though. In ECMAScript 5 or older environments, use String.prototype.indexOf, which returns -1 when a substring cannot be found:

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Ref: https://bit.ly/3fFFgZv