JavaScript Tutorial
JavaScript Alert, Prompt, and Confirm
JavaScript provides built-in dialog boxes that allow developers to interact with users directly through the browser. The three most commonly used dialog methods are alert(), prompt(), and confirm(). These methods are part of the Window Object and are widely used for notifications, confirmations, and simple user input.
The window object controls the browser itself.
1. JavaScript alert()
The alert() method displays a simple message box with an OK button. It is mainly used to show information or warnings to users.
Example
alert("Welcome to Learn2Kode!");
Key Points
- Pauses code execution until the user clicks OK
- Does not return any value
- Useful for notifications and debugging
2. JavaScript prompt()
The prompt() method displays a dialog box that asks the user for input. It includes a text field along with OK and Cancel buttons.
let name = prompt("Enter your name:");
console.log(name);
How It Works
- Returns user input as a string
- Returns null if the user clicks Cancel
- Often used for quick data collection
3. JavaScript confirm()
The confirm() method displays a dialog box with OK and Cancel options. It is commonly used for confirmations before performing actions.
let isConfirmed = confirm("Do you want to continue?");
if (isConfirmed) {
console.log("User agreed");
} else {
console.log("User cancelled");
}
Return Values
- true → User clicks OK
- false → User clicks Cancel
Comparison Table
| Method | Purpose | User Action | Return Value |
|---|---|---|---|
| alert() | Show message | OK | None |
| prompt() | Get user input | OK / Cancel | String / null |
| confirm() | Get confirmation | OK / Cancel | true / false |
Best Practices
- Avoid excessive use of alert boxes (bad user experience)
- Use confirm() for critical actions like delete or logout
- Validate prompt() input before using it
- Prefer custom modal dialogs for modern UI designs
Real-World Use Cases
- Alert users about form errors
- Confirm deletion of records
- Ask users for basic information
- Show warnings before leaving a page