Loading modal during the transition between two pages - javascript

I've got a login page that redirects you to an index page, the index page has this code:
<script type="text/javascript">
<div id="overlay">
<img src="loading.gif" alt="Loading" />
Loading...
</div>
jQuery:
$(window).load(function(){
$('#overlay').fadeOut();
});
</script>
It loads just a simple modal.
The issue is that the it shows the modal after a few seconds of delay. No just when the page is loading. The index page is heavy in content.
What I want is that just when for example chrome is loading (it's show a little circle spinning) my page show the modal.
The seconds of delay I think is why index its heavy.

When you add a function to the $(window).load() you are saying: call me when the page is finished loading. It sounds like you want to hide the spinner while the page is loading, not after. The problem is that jQuery might not be ready either, but if you don't have to support too many browsers, you can try it in a simple function instead of in load().
<script type="text/javascript">
$('#overlay').fadeOut()
</script>
Otherwise, if jQuery doesn't work because it isn't ready yet, then you may have to write the fadeOut logic yourself.

Your example is a little odd. Maybe just some reformatting of your code?
<div id="overlay">
<img src="loading.gif" alt="Loading" />
Loading...
</div>
<script type="text/javascript">
// Using the shorthand jQuery ready code. Basically
// this will add an anonymous function to a stack
// and when the document's ready event fires, it
// goes through the stack and runs anything you've
// added. So, document is ready, no run:
$(function(){
$('#overlay').fadeOut();
});
</script>
Or maybe your question is more about the difference between load event in window and document's ready event. See this for more window.onload vs $(document).ready()

Related

Window is loading first than DOM with jQuery on Google Chrome

I'm new to jQuery.I have learned that DOM content will be loaded first and then window.onload event will occur as all the style sheets and images have to be loaded.
But this doesn't turn out for me with the following code
<!DOCTYPE html>
<html>
<head>
<title>Add Event Listener</title>
<script type="text/javascript" src="../jquery-3.2.1.js"></script>
<script type="text/javascript" >
$(document).ready(function(){
alert("DOM Loaded");
});
$(window).on("load",function(){
alert("Window Loaded");
});</script>
</head>
<body>
</body>
</html>
After Opening this on Google Chrome (63.0.3239.108) I'm getting an alert that Window is Loaded prior to the alert of "DOM Loaded".
Same problem with Microsoft Edge (40.15063.0.0)
But,this works fine with Firefox(57.0.3)
Can anyone explain this?
Thanks in advance !
This Question is not a duplicate of
window.onload seems to trigger before the DOM is loaded (JavaScript)
That is because you test it without any image to load...
So all the markup has been parsed and all loaded. So the load event occurs.
Then when the script has been parsed, the ready occurs.
It usually is the script that is parsed faster, when there is images to load.
See below what happens when there is one.
$(document).ready(function(){
alert("DOM Loaded");
});
$(window).on("load",function(){
alert("Window Loaded");
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<img src="https://static.pexels.com/photos/132037/pexels-photo-132037.jpeg">
They are events and are triggered by a state being achieved. They are not interdependent events, so they have no fixed order.
window.onload fires once all resources declared in the html document are downloaded.
document.onload fires once the dom is built.
They are not dependent on each other. The dom can be built prior to the last resource being downloaded. All of the resources could download prior to the dom being built.

Why use window.onload

I have tried finding an answer to this on my own, but only found instructions on how to use onload events. I seem to be missing the point.
I've been taught that if I want something to happen when the page loads, I should use window.onload like this:
<script>
window.onload = dosomething();
function dosomething()
{
window.alert('hello');
}
</script>
But now that I am thinking on my own I wonder what the point of doing that is. Because this also produces the same result:
<script>
dosomething();
function dosomething()
{
window.alert('hello');
}
</script>
Anything I put at the top inside <script> is going to execute anyway... so what's the point of window.onload?
If you're directly running your code with dosomething();, you're delaying your browser's rendering for the time it takes your JavaScript code to run.
You can try to insert your code to the <head> of your html document:
<!DOCTYPE html>
<html>
<head>
<script>
dosomething();
function dosomething()
{
window.alert('hello');
}
</script>
</head>
<body>
Does not render before the alert is dismissed!
</body>
</html>
You'll see that the page stays blank until you dismiss the alert. So every second the browser takes to run your JavaScript code is a second that your users have to wait for the site to be rendered.
Now if you change the code to be run on body's onload, the page gets rendered before the alert is shown:
<!doctype html>
<html>
<head>
<script>
function dosomething()
{
window.alert('hello');
}
</script>
</head>
<body onload="dosomething()">
This page gets rendered before the alert!
</body>
</html>
Consider these two blocks of code:
<head>
<script>
alert(document.getElementById('foo').value);
</script>
</head>
<body>
<input id="foo" value="hello">
</body>
<head>
<script>
window.onload = function() {
alert(document.getElementById('foo').value);
}
</script>
</head>
<body>
<input id="foo" value="hello">
</body>
In the first example, we'll get an error because the element you are referencing isn't found when the script runs - and so you are trying to get value of null.
In the second example, document.getElementById() will find the element with the id foo, because window.onload will get fired only when the complete DOM has been loaded and so the element is available.
window.onload will fire once the DOM has finished loading. In your example, the DOM is not required. However, the following code will fail if the DOM has not yet loaded:
function doSomething() {
alert(document.getElementById('test').innerText);
}
// Throws: TypeError: Cannot read property 'innerText' of null
Assuming your page contains an element with id test, it will alert its text.
waiting for the onload event assures you that all of your scripts and resources are loaded
Assume you are using jquery in your page and you invoked a function that uses it directly without onload , you can't guarantee that the jquery file has been loaded, which will lead to errors and possibly ruining your whole logic
The onload event is handy to make sure the page is fully loaded before you run a script. For your example above it doesn't make sense, but if your page is still loading an item on the bottom and you try to call it then nothing will run.
I recommend using jQuery and using the ready function. This way you will ensure your page is completely loaded.
$( document ).ready(function() {
// This will only run after the whole page is loaded.
});
If you don't want to load query, just put your javascript at the bottom of the page. It's best practice, and ensures the DOM is loaded in full.
For more info on the jquery ready function go here: https://api.jquery.com/ready/

Why is this jQuery click function not working?

Code:
<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"></script>
<script type="text/javascript">
$("#clicker").click(function () {
alert("Hello!");
$(".hide_div").hide();
});
</script>
The above code doesn't work. When I click on #clicker, it doesn't alert and and it doesn't hide. I checked the console and I get no errors. I also checked to see if JQuery was loading and indeed it is. So not sure what the issue is. I also did a document ready function with an alert and that worked so not sure what I am doing wrong. Please help. Thanks!
You are supposed to add the javascript code in a $(document).ready(function() {}); block.
i.e.
$(document).ready(function() {
$("#clicker").click(function () {
alert("Hello!");
$(".hide_div").hide();
});
});
As jQuery documentation states: "A page can't be manipulated safely until the document is "ready." jQuery detects this state of readiness for you. Code included inside $( document ).ready() will only run once the page Document Object Model (DOM) is ready for JavaScript code to execute"
I found the best solution for this problem by using ON with $(document).
$(document).on('click', '#yourid', function() { alert("hello"); });
for id start with see below:
$(document).on('click', 'div[id^="start"]', function() {
alert ('hello'); });
finally after 1 week I not need to add onclick triger.
I hope this will help many people
Your code may work without document.ready() just be sure that your script is after the #clicker. Checkout this demo: http://jsbin.com/aPAsaZo/1/
The idea in the ready concept. If you sure that your script is the latest thing in your page or it is after the affected element, it will work.
<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>JS Bin</title>
</head>
<body>
<script src="https://code.jquery.com/jquery-latest.min.js"
type="text/javascript"></script>
<a href="#" id="clicker" value="Click Me!" >Click Me</a>
<script type="text/javascript">
$("#clicker").click(function () {
alert("Hello!");
$(".hide_div").hide();
});
</script>
</body>
</html>
Notice:
In the jsbin demo replace http with https there in the code, or use this variant Demo
Try adding $(document).ready(function(){ to the beginning of your script, and then });. Also, does the div have the id in it properly, i.e., as an id, not a class, etc.?
You have to wrap your Javascript-Code with $(document).ready(function(){});Look this JSfiddle.
JS Code:
$(document).ready(function() {
$("#clicker").click(function () {
alert("Hello!");
$(".hide_div").hide();
});
});
Be sure there is nothing on your button (such a div or a trasparent img) that keeps from clicking the button.
It sounds stupid, but sometimes we think that jQuery is not working and all that stuffs and the problem is on the positioning of DOM elements.
You can use $(function(){ // code }); which is executed when the document is ready to execute the code inside that block.
$(function(){
$('#clicker').click(function(){
alert('hey');
$('.hide_div').hide();
});
});
Just a quick check, if you are using client-side templating engine such as handlebars, your js will load after document.ready, hence there will be no element to bind the event to, therefore either use onclick handler or use it on the body and check for current target
Proper Browser Reload
Just a quick check as well if you keep your js files separately: make sure to reload your resources properly. Browsers will usually cache files, so just assure that i.e. a former typo is corrected in your loaded resources.
See this answer for permanent cache disabling in Chrome/Chromium. Otherwise you can generally force a full reload with Ctrl+F5 or Shift+F5 as mentioned in this answer.

Appending text/elements to a DIV tag

How do I add text/elements to a target element (div) using getElementById (without jquery) when the page loads?
Here's my markup currently:
<html>
<head>
<title>test</title>
<script language="javascript">
/document.getElementById('content').innerHTML = 'Fred Flinstone';
</script>
</head>
<body>
<div id="content">
dssdfs
</div>
</body>
</html>
<script type="text/javascript">
function dothis()
{
document.getElementByID('content').innerHTML = 'Fred Flinstone';
}
</script>
<body onLoad="dothis()">
...
</body>
I think what is happening is that your script is executing before your document is ready. Try placing your javascript in a body load event.
The quickest (although not the best) way to do it is to put your script block towards the end of the HTML file (after the <div> you wish to modify).
The better way to do it is to register for DOM load notification
If you want it to execute after the page loads, then you need to observe the DOM loaded event. You can do that by subscribing to the DOM load event in the script block and then put the code that manipulates the DIV in the event handler.
The tricky part is that different browsers may need slightly different ways to register to be notified when the DOM is loaded (that's were jQuery or a different library becomes useful)
Here's some more information about different ways to register for a callback to be called when the DOM is loaded. The information may be a bit out of date as more modern versions of the popular browsers have become more standards compliant now: http://www.javascriptkit.com/dhtmltutors/domready.shtml

jQuery or JavaScript auto click

How can I auto click on the link on page load? I have been trying for ages but id does not work.
<link rel="stylesheet" type="text/css" href="leightbox.css" />
<script type="text/javascript" src="prototype.js"></script>
<script type="text/javascript" src="leightbox.js"></script>
</head>
<body>
<div class="content">
<p> Click here to activate leightbox popup.</p>
</div>
<!----------// POPUP (ON CLICK) //---------->
<div id="pop02" class="leightbox">
×
<div class="scrollbox">
<h1>This popup loads upon clicking a trigger link.</h1>
text</div>
</div>
</body>
You haven't provided your javascript code, but the usual cause of this type of issue is not waiting till the page is loaded. Remember that most javascript is executed before the DOM is loaded, so code trying to manipulate it won't work.
To run code after the page has finished loading, use the $(document).ready callback:
$(document).ready(function(){
$('#some-id').trigger('click');
});
First i tried with this sample code:
$(document).ready(function(){
$('#upload-file').click();
});
It didn't work for me. Then after, tried with this
$(document).ready(function(){
$('#upload-file')[0].click();
});
No change. At last, tried with this
$(document).ready(function(){
$('#upload-file')[0].click(function(){
});
});
Solved my problem. Helpful for anyone.
$(document).ready(function(){
$('#some-id').trigger('click');
});
did the trick.
$(document).ready(function(){
$('.lbOn').click();
});
Suppose this would work too.
In jQuery you can trigger a click like this:
$('#foo').trigger('click');
More here:
http://api.jquery.com/trigger/
If you want to do the same using prototype, it looks like this:
$('foo').simulate('click');
You are trying to make a popup work maybe? I don't know how to emulate click, maybe you can try to fire click event somehow, but I don't know if it is possible. More than likely such functionality is not implemented, because of security and privacy concerns.
You can use div with position:absolute to emulate popup at the same page. If you insist creating another page, I cannot help you. Maybe somebody else with more experience will add his 15 cents.

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