hidden

Summary

document.hidden returns true if the document is hidden or false if it is visible at all

Syntax

Note: This property is read-only.

var state = document.hidden;

Return Value

Returns an object of type BooleanBoolean

hidden is a boolean value which is true if the page is not visible, even the smallest part, and this typically happens when the tab is in background or the browser is minimized. It’s important to note that this rule has some exceptions for accessibility tools that act in full-screen mode.

Examples

var timer = 0;
var PERIOD_VISIBLE = 1000;
var PERIOD_NOT_VISIBLE = 60000;

function onLoad() {
   timer = setInterval(checkEmail, (document.hidden) ? PERIOD_NOT_VISIBLE : PERIOD_VISIBLE);
   if(document.addEventListener) document.addEventListener("visibilitychange", visibilityChanged);
}

function visibilityChanged() {
   clearTimeout(timer);
   timer = setInterval(checkEmail, (document.hidden) ? PERIOD_NOT_VISIBLE : PERIOD_VISIBLE);
}

function checkEmail() {
   // Check server for new messages
}

window.onload = onLoad;

Notes

Remarks

The Visibility API provides Web applications with the means to programmatically determine the current visibility of a page and be notified of visibility changes. You can use this property to determine whether a page is visible or not. If it is not visible, you can throttle page activity and resource usage to create more power- and CPU-efficient applications. This is a property of the document object. You can also use the visibilityState and visibilitychange properties to learn more about the page visibility state.

Related specifications

Page Visibility: Recommendation

Attributions

Microsoft Developer Network: [Windows Internet Explorer API reference Article]