w3resource

JavaScript: Generates a string id (specified length) of random characters

JavaScript Function: Exercise-20 with Solution

Write a JavaScript function that generates a string id (specified length) of random characters.

Sample character list : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

Sample Solution: -

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Generates a string id (specified length) of random characters</title>
</head>
<body>
  
</body>
</html>

JavaScript Code:

function makeid(l)
{
var text = "";
var char_list = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
for(var i=0; i < l; i++ )
{  
text += char_list.charAt(Math.floor(Math.random() * char_list.length));
}
return text;
}
console.log(makeid(8));

Sample Output:

4SGqCfrz

Flowchart:

Flowchart: JavaScript function: Generates a string id (specified length) of random characters

Live Demo:

See the Pen JavaScript - Generates a string id (specified length) of random characters-function-ex- 20 by w3resource (@w3resource) on CodePen.


Contribute your code and comments through Disqus.

Previous: Write a JavaScript function that returns array elements larger than a number.
Next: Write a JavaScript function to get all possible subset with a fixed length (for example 2) combinations in an array.

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