# Replace

The `replace` method allows us to replace a character, word, or sentence with a string. For example.

```javascript
let str = "Hello World!";
let new_str = str.replace("Hello", "Hi");

console.log(new_str);

// Result: Hi World!
```

{% hint style="warning" %}
To replace a value on all instances of a [regular expression](/js-101/regular-expression.md) with a `g` modifier is set.
{% endhint %}

It searches for a string for a value or a regular expression and returns a new string with the value(s) replaced. It doesn't change the original string. Let's see the global case-insensitive replacement example.

```javascript
let text = "Mr Blue has a blue house and a blue car";
let result = text.replace(/blue/gi, "red"); 

console.log(result); 
//Result: Mr red has a red house and a red car 
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://js201.gitbook.io/js-101/strings/replace.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.