---
id: 56533eb9ac21ba0edf2244ba
title: Understand String Immutability
challengeType: 1
---
## Description
In JavaScript, String values are immutable, which means that they cannot be altered once created.
For example, the following code:
var myStr = "Bob";
myStr[0] = "J";
cannot change the value of myStr to "Job", because the contents of myStr cannot be altered. Note that this does not mean that myStr cannot be changed, just that the individual characters of a string literal cannot be changed. The only way to change myStr would be to assign it with a new string, like this:
var myStr = "Bob";
myStr = "Job";
## Instructions
Correct the assignment to myStr so it contains the string value of Hello World using the approach shown in the example above.
## Tests
```yml
tests:
- text: myStr should have a value of Hello World
testString: assert(myStr === "Hello World", 'myStr should have a value of Hello World');
- text: Do not change the code above the line
testString: assert(/myStr = "Jello World"/.test(code), 'Do not change the code above the line');
```
## Challenge Seed
```js
// Setup
var myStr = "Jello World";
// Only change code below this line
myStr[0] = "H"; // Fix Me
```
### After Test
```js
(function(v){return "myStr = " + v;})(myStr);
```
## Solution
```js
var myStr = "Jello World";
myStr = "Hello World";
```