Javascript document loaded function

Window: load event

The load event is fired when the whole page has loaded, including all dependent resources such as stylesheets, scripts, iframes, and images. This is in contrast to DOMContentLoaded , which is fired as soon as the page DOM has been loaded, without waiting for resources to finish loading.

This event is not cancelable and does not bubble.

Note: All events named load will not propagate to Window , even with bubbles initialized to true . To catch load events on the window , that load event must be dispatched directly to the window .

Note: The load event that is dispatched when the main document has loaded is dispatched on the window , but has two mutated properties: target is document , and path is undefined . These two properties are mutated due to legacy conformance.

Syntax

Use the event name in methods like addEventListener() , or set an event handler property.

addEventListener("load", (event) => >); onload = (event) => >; 

Event type

Examples

Log a message when the page is fully loaded:

.addEventListener("load", (event) =>  console.log("page is fully loaded"); >); 

The same, but using the onload event handler property:

.onload = (event) =>  console.log("page is fully loaded"); >; 

Live example

HTML

div class="controls"> button id="reload" type="button">Reloadbutton> div> div class="event-log"> label for="eventLog">Event log:label> textarea readonly class="event-log-contents" rows="8" cols="30" id="eventLog">textarea> div> 

body  display: grid; grid-template-areas: "control log"; > .controls  grid-area: control; display: flex; align-items: center; justify-content: center; > .event-log  grid-area: log; > .event-log-contents  resize: none; > label, button  display: block; > #reload  height: 2rem; > 

JavaScript

const log = document.querySelector(".event-log-contents"); const reload = document.querySelector("#reload"); reload.addEventListener("click", () =>  log.textContent = ""; setTimeout(() =>  window.location.reload(true); >, 200); >); window.addEventListener("load", (event) =>  log.textContent += "load\n"; >); document.addEventListener("readystatechange", (event) =>  log.textContent += `readystate: $document.readyState>\n`; >); document.addEventListener("DOMContentLoaded", (event) =>  log.textContent += `DOMContentLoaded\n`; >); 

Result

Specifications

Browser compatibility

BCD tables only load in the browser

See also

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This page was last modified on Apr 8, 2023 by MDN contributors.

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Источник

How to use Document onload in JavaScript

In this tutorial, we will go through how to execute a function when the page has loaded in JavaScript using onload .

window.onload Example

The JavaScript window.onload utility will fire when all the content in the page has loaded including images, CSS, scripts .etc. Here is an example that will run a function containing an alert() message:

window.onload = function()  alert('Loaded!'); >; 

Here is another example using addEventListener :

window.addEventListener("load", function() alert('Loaded!'); >); 

document.onload Example

The document.onload utility will fire when the DOM is read, excluding images and external content.

document.onload = function()  alert('Loaded!'); >; 

jQuery Document onload Example

If you’re using jQuery, here is an example of how to create a function that will run on DOM loaded:

$(document).ready(function()  /* code to run */ >); 

Here is another example using addEventListener :

document.addEventListener("DOMContentLoaded", function() alert('Loaded!'); >); 

The difference with document object is it uses the DOMContentLoaded property to indicate the DOM has loaded.

Источник

Window: DOMContentLoaded event

The DOMContentLoaded event fires when the HTML document has been completely parsed, and all deferred scripts ( and ) have downloaded and executed. It doesn’t wait for other things like images, subframes, and async scripts to finish loading.

DOMContentLoaded does not wait for stylesheets to load, however deferred scripts do wait for stylesheets, and the DOMContentLoaded event is queued after deferred scripts. Also, scripts which aren’t deferred or async (e.g. ) will wait for already-parsed stylesheets to load.

The original target for this event is the Document that has loaded. You can listen for this event on the Window interface to handle it in the capture or bubbling phases. For full details on this event please see the page on the Document: DOMContentLoaded event.

A different event, load , should be used only to detect a fully-loaded page. It is a common mistake to use load where DOMContentLoaded would be more appropriate.

This event is not cancelable.

Syntax

Use the event name in methods like addEventListener() , or set an event handler property.

addEventListener("DOMContentLoaded", (event) => >); onDOMContentLoaded = (event) => >; 

Источник