THE WORLD'S LARGEST WEB DEVELOPER SITE
×

JS Tutorial

JS HOME JS Introduction JS Where To JS Output JS Statements JS Syntax JS Comments JS Variables JS Operators JS Arithmetic JS Assignment JS Data Types JS Functions JS Objects JS Events JS Strings JS String Methods JS Numbers JS Number Methods JS Arrays JS Array Methods JS Array Sort JS Array Iteration JS Dates JS Date Formats JS Date Get Methods JS Date Set Methods JS Math JS Random JS Booleans JS Comparisons JS Conditions JS Switch JS Loop For JS Loop While JS Break JS Type Conversion JS Bitwise JS RegExp JS Errors JS Scope JS Hoisting JS Strict Mode JS this Keyword JS Let JS Const JS Debugging JS Style Guide JS Best Practices JS Mistakes JS Performance JS Reserved Words JS Versions JS Version ES5 JS Version ES6 JS JSON

JS Forms

JS Forms Forms API

JS Objects

Object Definitions Object Properties Object Methods Object Constructors Object Prototypes

JS Functions

Function Definitions Function Parameters Function Invocation Function Call Function Apply Function Closures

JS HTML DOM

DOM Intro DOM Methods DOM Document DOM Elements DOM HTML DOM CSS DOM Animations DOM Events DOM Event Listener DOM Navigation DOM Nodes DOM Collections DOM Node Lists

JS Browser BOM

JS Window JS Screen JS Location JS History JS Navigator JS Popup Alert JS Timing JS Cookies

JS AJAX

AJAX Intro AJAX XMLHttp AJAX Request AJAX Response AJAX XML File AJAX PHP AJAX ASP AJAX Database AJAX Applications AJAX Examples

JS JSON

JSON Intro JSON Syntax JSON vs XML JSON Data Types JSON Objects JSON Arrays JSON Parse JSON Stringify JSON PHP JSON HTML JSON JSONP

JS Examples

JS Examples JS HTML DOM JS HTML Input JS HTML Objects JS HTML Events JS Browser JS Quiz JS Certificate

JS References

JavaScript Objects HTML DOM Objects


JavaScript Popup Boxes


JavaScript has three kind of popup boxes: Alert box, Confirm box, and Prompt box.


Alert Box

An alert box is often used if you want to make sure information comes through to the user.

When an alert box pops up, the user will have to click "OK" to proceed.

Syntax

window.alert("sometext");

The window.alert() method can be written without the window prefix.

Example

alert("I am an alert box!");
Try it Yourself »

Confirm Box

A confirm box is often used if you want the user to verify or accept something.

When a confirm box pops up, the user will have to click either "OK" or "Cancel" to proceed.

If the user clicks "OK", the box returns true. If the user clicks "Cancel", the box returns false.

Syntax

window.confirm("sometext");

The window.confirm() method can be written without the window prefix.

Example

if (confirm("Press a button!")) {
    txt = "You pressed OK!";
} else {
    txt = "You pressed Cancel!";
}
Try it Yourself »


Prompt Box

A prompt box is often used if you want the user to input a value before entering a page.

When a prompt box pops up, the user will have to click either "OK" or "Cancel" to proceed after entering an input value.

If the user clicks "OK" the box returns the input value. If the user clicks "Cancel" the box returns null.

Syntax

window.prompt("sometext","defaultText");

The window.prompt() method can be written without the window prefix.

Example

var person = prompt("Please enter your name", "Harry Potter");

if (person == null || person == "") {
    txt = "User cancelled the prompt.";
} else {
    txt = "Hello " + person + "! How are you today?";
}
Try it Yourself »

Line Breaks

To display line breaks inside a popup box, use a back-slash followed by the character n.

Example

alert("Hello\nHow are you?");
Try it Yourself »