I dynamically add an image on my page :
<div class="simple_overlay" id="overlay">
<img src="" />
</div>
<script type="text/javascript">
$(function() {
$("a[rel]").overlay({
var source = this.getTrigger().attr('href');
this.getOverlay().find("img").attr({'src': source});
});
});
</script>
Now, I need to get width of the new image and calculate margin-left corresponding to it. Native jQuery Tools methods doesn't work, because when overlay is loading, image hasn't yet loaded and container #overlay width is 0.
Is there any option to emulate callback on this chain, so i can use width() right after attr() has evaluated?
Use the images load event (not to be confused with window.load), like this:
$("a[rel]").overlay({
var source = this.getTrigger().attr('href');
this.getOverlay().find("img").one('load', function() {
//run your code here, the image is loaded and is "this"
}).each(function() {
if (this.complete) $(this).load(); //trigger load, handles from cache cases
}).attr({'src': source});
});
This uses .one() to run your code only once. The load event fires when that image is loaded...but this doesn't always fire when loading it from cache (depending on browser), which is what the .each() is for. If the browser loaded it from cache and fired the event...that's ok too, the .one() handles that, code still runs once in every case :)
Related
I need to execute some JavaScript code when the page has fully loaded. This includes things like images.
I know you can check if the DOM is ready, but I don’t know if this is the same as when the page is fully loaded.
That's called load. It came waaaaay before DOM ready was around, and DOM ready was actually created for the exact reason that load waited on images.
window.addEventListener('load', function () {
alert("It's loaded!")
})
For completeness sake, you might also want to bind it to DOMContentLoaded, which is now widely supported
document.addEventListener("DOMContentLoaded", function(event){
// your code here
});
More info: https://developer.mozilla.org/en-US/docs/Web/Events/DOMContentLoaded
Usually you can use window.onload, but you may notice that recent browsers don't fire window.onload when you use the back/forward history buttons.
Some people suggest weird contortions to work around this problem, but really if you just make a window.onunload handler (even one that doesn't do anything), this caching behavior will be disabled in all browsers. The MDN documents this "feature" pretty well, but for some reason there are still people using setInterval and other weird hacks.
Some versions of Opera have a bug that can be worked around by adding the following somewhere in your page:
<script>history.navigationMode = 'compatible';</script>
If you're just trying to get a javascript function called once per-view (and not necessarily after the DOM is finished loading), you can do something like this:
<img src="javascript:location.href='javascript:yourFunction();';">
For example, I use this trick to preload a very large file into the cache on a loading screen:
<img src="bigfile"
onload="this.location.href='javascript:location.href=\'javascript:doredir();\';';doredir();">
Try this it Only Run After Entire Page Has Loaded
By Javascript
window.onload = function(){
// code goes here
};
By Jquery
$(window).bind("load", function() {
// code goes here
});
Try this code
document.onreadystatechange = function () {
if (document.readyState == "complete") {
initApplication();
}
}
visit https://developer.mozilla.org/en-US/docs/DOM/document.readyState for more details
Javascript using the onLoad() event, will wait for the page to be loaded before executing.
<body onload="somecode();" >
If you're using the jQuery framework's document ready function the code will load as soon as the DOM is loaded and before the page contents are loaded:
$(document).ready(function() {
// jQuery code goes here
});
the window.onload event will fire when everything is loaded, including images etc.
You would want to check the DOM ready status if you wanted your js code to execute as early as possible, but you still need to access DOM elements.
You may want to use window.onload, as the docs indicate that it's not fired until both the DOM is ready and ALL of the other assets in the page (images, etc.) are loaded.
In modern browsers with modern javascript (>= 2015) you can add type="module" to your script tag, and everything inside that script will execute after whole page loads. e.g:
<script type="module">
alert("runs after") // Whole page loads before this line execute
</script>
<script>
alert("runs before")
</script>
also older browsers will understand nomodule attribute. Something like this:
<script nomodule>
alert("tuns after")
</script>
For more information you can visit javascript.info.
And here's a way to do it with PrototypeJS:
Event.observe(window, 'load', function(event) {
// Do stuff
});
The onload property of the GlobalEventHandlers mixin is an event
handler for the load event of a Window, XMLHttpRequest, element,
etc., which fires when the resource has loaded.
So basically javascript already has onload method on window which get executed which page fully loaded including images...
You can do something:
var spinner = true;
window.onload = function() {
//whatever you like to do now, for example hide the spinner in this case
spinner = false;
};
Completing the answers from #Matchu and #abSiddique.
This:
window.addEventListener('load', (event) => {
console.log('page is fully loaded');
});
Is the same as this but using the onload event handler property:
window.onload = (event) => {
console.log('page is fully loaded');
};
Source:
https://developer.mozilla.org/en-US/docs/Web/API/Window/load_event
Live example here:
https://developer.mozilla.org/en-US/docs/Web/API/Window/load_event#live_example
If you need to use many onload use $(window).load instead (jQuery):
$(window).load(function() {
//code
});
2019 update: This is was the answer that worked for me. As I needed multiple ajax requests to fire and return data first to count the list items.
$(document).ajaxComplete(function(){
alert("Everything is ready now!");
});
How do I delay some jQuery / JavaScript function until all the images on a page have finished loading?
Actually, the jQuery function I'm talking about is for setting the offset position for a div. The problem is that the page resizes once the images are loaded completely, so the offset is wrong.
For the jQuery function refer to this question: Issues with Fixed div on bottom of page that stops at given place
You can use the onload event which runs after all images or external resources are loaded:
$(window).load(function(){
// your code here, all images loaded
});
You can also use the load event for individual images and run your code when they have loaded:
$('img.ImageClass').load(function(){
// The image loaded....
});
just write the function under a variable like
function newfunction(){
//put all the stuff here
}
after that call this function on every image load like
$('img').load(function(){
newfunction()
})
from this the newfunction will call everytime a new image load.
I am trying to obtain an element width using the following code just before the </body>
<script type="text/javascript" charset="utf-8">
$(document).ready(function(){
var diff = $('div.canvas img.photo').get(1).width;
console.log(diff);
});
</script>
but it logs undefined. However, if I run $('div.canvas img.photo').get(1).width directly in the Chrome/Firebug console, it returns the correct width. The image is not being loaded with Javascript, so should be in place when the document ready fires. What am I doing wrong?
No, it shouldn't. document.ready fires when all HTML has been loaded, but not the images. If you want to wait until all images are loaded, use window.load.
Example:
$(window).load(function(){
var diff = $('div.canvas img.photo').get(1).width;
console.log(diff);
});
Also, as some people have pointed out, you were attempting to get the property ".width" twice.
If at all possible, set a width on the imagetags in CSS. That way, you can safely use document.ready for your code. Using window.load will naturally delay the execution of your script, could be a second, could be ten, depending on the speed of the clients connection, and the amount of content on your page. This could cause unwanted jumps and jitters if you're performing any styling.
img isn't being loaded on DOM ready. docs:
While JavaScript provides the load event for executing code when a page is rendered, this event does not get triggered until all assets such as images have been completely received. In most cases, the script can be run as soon as the DOM hierarchy has been fully constructed. The handler passed to .ready() is guaranteed to be executed after the DOM is ready, so this is usually the best place to attach all other event handlers and run other jQuery code. When using scripts that rely on the value of CSS style properties, it's important to reference external stylesheets or embed style elements before referencing the scripts.
change to this:
$(window).load(function(){
var diff = $('div.canvas img.photo').get(1).width;
console.log(diff.width);
});
Image's width would only be available when its loaded completely.
jQuery supports onload event on every images too.
You can use,
$('div.canvas img.photo').load(function(){
// here the image (or all images which match selector) has been loaded.
}
The problem is that your image is not loaded yet when you try to get its dimentions. To make it work wrap your code into $(window).load. Or another option. If you know the sizes of the image you can provide width and height attributes, then it's going to work even inside DOMContentLoaded. Sometimes it's preferable because onload event takes longer to fire then 'DOMContentLoaded'.
Otherwise you would need to use $(window).load, see #Andreas Carlbom answer.
Can you list the difference between onload() and $(document).ready(function(){..}) functions in the using jQuery?
the load event (a.k.a "onload") on the window and/or body element will fire once all the content of the page has been loaded -- this includes all images, scripts, etc... everything.
In contrast, jquery's $(document).ready(...) function will use a browser-specific mechanism to ensure that your handler is called as soon as possible after the HTML/XML dom is loaded and accessible. This is the earliest point in the page load process where you can safely run script that intends to access elements in the page's html dom. This point arrives earlier (often much earlier) than the final load event, because of the additional time required to load secondary resources (like images, and such).
The main differences between the two are:
Body.Onload() event will be called only after the DOM and associated resources like images got loaded, but jQuery's document.ready() event will be called once the DOM is loaded i.e., it wont wait for the resources like images to get loaded. Hence, the functions in jQuery's ready event will get executed once the HTML structure is loaded without waiting for the resources.
We can have multiple document.ready() in a page but Body.Onload() event cannot.
Document.ready() function triggers as soon as HTML DOM loaded. But the onload() function will trigger after HTML DOM, all the body content like images loaded.
body.onload() cares about both HTML structure and assoicated resources where as document.ready() cares only about the HTML structure.
onload() fires when all the content (everything) on the targeted eleement is fully loaded like CSS, images etc.
$.ready indicates that code in it need to be executed once the targeted elements content loaded and ready to be manipulated by script. It won't wait for the images to load for executing the jQuery script.
.
Ex(body onload):
<body onload="loadBody()">
<script>
function myFunction() {
alert("Page is loaded");
}
</script>
</body
Ex(onload on an element):
<img src="w3html.gif" onload="loadImg()" width="100" height="132">
<script>
function loadImg() {
alert("Image is loaded");
}
</script>
Ex3 ($.ready):
<script type = "text/javascript">
$(document).ready(function() {
alert("$(document).ready fired");
});
</script>
Onload take care about DOM and resources: it checks if images are loaded, script are ready to run and much more.
$.ready simply check if we have read the full DOM of the page.
Please check out this link for more explain and example: http://dailygit.com/difference-between-document-ready-and-window-load-in-jquery/
I’m using jQuery for my project. $(function(){...}) fires the function “when the DOM is ready” — this doesn’t say that all images are loaded, right?
Is there an event that gets fired when every image is loaded too?
I guess you mean
http://api.jquery.com/ready/
versus
http://api.jquery.com/load-event/
Example: Run a function when the page is fully loaded including graphics.
$(window).load(function () {
// run code
});
without jQuery:
window.onload=function() {
alert(document.images.length);
}
You can check on load event of image tag. This will get fired when image loading completes.
$("img").load(function(){
// your code
});
window.onload will solve this, I wrote about this there: http://amrelgarhy.com/blog/how-to-tell-when-images-have-loaded/