# Default Parameter

A parameter value used when the caller supplies undefined or omits the argument.

## What is **Default Parameter** in JavaScript?

**Default Parameter** — A parameter value used when the caller supplies undefined or omits the argument.

```javascript
function greet(name = "Guest") {
    return `Hello, ${name}`;
}
```

Level: Apprentice · [More JavaScript terms at this level](https://www.ask-codey.com/glossary/subjects/javascript/apprentice)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/default-parameter