creating a visible on load Pre-loader Page - javascript

Trying to replicate the pre-loader page on load the SVG and a background image appears and as soon as the user scrolls the page scrolls to the content and the page-loader is not visible or can be reached again unless you refresh the page, not sure how to tackle this, any help to point me in the right direction would be great- I have tried diseminating the said page.

there are a few ways to accomplish this, a simple starting point could be something like this:
basic html outline:
<div id="loader">
LOADING Image/content
</div>
<div id="body">
website body
</div>
CSS
#body{display:none;}
jQuery
$(document).ready(function(){
$("#loader").hide();
$("#body").show();
});
noscript fallback
<noscript>
<style>#loader{display:none;}#body{display:block !important;}</style>
</noscript>
Basically, this code has two divs the loader and the body, the body is set as display none in the CSS. When the page is ready, jquery is triggered to hide the loader and show the body.
The noscript fall back will set body to visible when javascript is disabled.
There are multiple ways to accomplish, this is just one idea.

Out of one of a hundred different ways, my initial thoughts were along these lines:
Wrap your main content in a wrapper with position relative and give it an offset from the top by 100% of the window width
Make the page-loader 100% height and width and position fixed
Offset the wrapper before the page is fully loaded, and then just transition it to 0 offset once the page had loaded
See a working jsfiddle here

Create an element (Div) that covers the whole screen.
Behind it (smaller z-index) add a Div container that holds all the images.
Add in JavaScript a load event function to all images:
image.onload = function() {
//image was loaded
}
Hide the cover Div when all images was loaded.
How to know when all images were loaded? add a counter or use a Promise.
Add overflow: none to disable scrolling, and add click event or scroll event (using jQuery) and set overflow to auto.
There are a lot of ways to implement each of these sections.

Related

Replacing a div id and changing css height (with overflow-y: "scroll") breaks javascript lazy load

I'm doing 2 changes on a div with jQuery:
if (jQuery("#geodir-wrapper-content").length > 0){
document.getElementById("geodir-wrapper-content").id = 'geodir_content';
}
as well as:
jQuery("#geodir_content").css({
height: "calc(100vh - "+contentHeight+"px)",
'overflow-y': "scroll",
'-webkit-overflow-scrolling': "touch"
});
The result is exactly what I want: the right shape and the right CSS classes are applied to the div.
The content within this div has images loading with lazy load javascript. The first images load fine, but when scrolling inside this div the new images don't load. They only load when the window gets resized or if there is a possibility so scroll on the main page (which I don't have on my final design).
I've set up a jsfiddle with the complete setup. Note that I can't modify the lazy load javascript as it's part of a plugin, so I'd like to find a workaround in my own code.

Issues with Fixed div on bottom of page that stops at given place

We needed a footer toolbar that stays at the bottom of the page, and sticks to some area when page is scrolled below that area.
We did achieved this using following script:
fixed div on bottom of page that stops in given place
But there is an issue on some page where the footer toolbar just disappears from the page, and then appear again when page is scrolled down further.
We found that this particular issue appears only on few page, when the page has some contents like Images, Video, or Ajax load other content where the content is filled in (or space is being filled) after page has loaded.
I have no clue how to fix this.
Here is the link from live site with problem page.
http://www.sandiegopchelp.com/services/cellphone-repair/htc/
http://www.sandiegopchelp.com/top-10-tips-to-help-secure-your-computer/
http://www.sandiegopchelp.com/notes-on-the-phablet-does-the-world-need-one/
It is usually more visible on blog posts with many comments. May be due to Disqus comments being loaded after the page has loaded completely.
How does this look?
http://jsfiddle.net/LukeGT/NxSc3/
$(window).scroll(function() {
$('#bar').css('position', 'static');
console.log($('#bar').position().top);
console.log($(window).scrollTop() + $(window).height());
if ($(window).scrollTop() + $(window).height() < $('#bar').position().top + $('#bar').height()) {
$('#bar').css('position', 'fixed');
}
});
setTimeout(function() {
$('#extra').show();
}, 1000);​
I simulated the late loading of images by just showing a few extra divs after 1 second. I believe the problem arises from the fact that the height of the page changes after the code for the bar runs, so it's behaving as it should if the page were shorter (without the images/ajax etc).
What I do instead is position the bar in it's place at the bottom of the page each time the page is scrolled, calculate its height from the top there, and compare this with the scroll height. If we're too far up, it positions the bar in a fixed position at the base of the page, and otherwise leaves it alone. It works smoothly in Chrome, but I haven't tested elsewhere.
I guess this is a problem with the $(window).height() function. Check here. For all the dynamic contents like Images, Video or Ajax-loaded content the height is not added to the result of $(window).height() unless it is specified somewhere in the HTML or CSS (and from the referred link I see this happens only in Chrome. You might want to confirm on this though). To those dynamic contents you can either try adding the height attribute in html or height attribute in the corresponding style.
This is not the answer but i have found something while inspecting your website...
This is you actual HTML when its working fine as you want..
<div class="footer-toolbar-container" id="sticky_for_a_while" style="position: fixed; ">
but when it is not working, the Position attribute is changing from Fixed to Relative .
<div class="footer-toolbar-container" id="sticky_for_a_while" style="position: relative; ">
you can check you script for that or post you script here...
At initial state, your div is in position: relative so its offset is based on the container element, not on the total height of the page. The variable stickyOffset is set based on that relative offset, that is why it gets clip down sooner than expected while scrolling and also why it works in your JSFiddle as the container there is the page (Iframe) itself.
In your $(document).ready function, you'll need to add the offset of not only the footer but also the rest of the offset on top of the containing element so that the offset is based on the total page instead of the containing div.
Hope that helps.
By looking at your example on http://www.sandiegopchelp.com/services/cellphone-repair/htc/ using chrome, I can see that your footer disappears when it gets at the "related links" section. At this moment, you set the position of the footer to "relative" so it will replace it in the regular flow of the document and its position is actually below the "related links" section which is why it disappears off screen (below "related links").
but you calculated the position at which it should become relative on page load only where you should have recalculated it after having added the "related links" section as it changes the page height (I understood that you added afterward, am I right?).
Try adding a zero height div just above the position of the sticky div, which will remain at that position as the page resizes, then check that position as you scroll to determine the position where the sticky div should stop.
Finally got it fixed by two techniques, setting explicit height wherever possible using CSS and delaying jQuery function after all images are loaded. Refer this: Delay some jQuery function until all images are loaded completely

JScrollPane not working properly with hidden content

I installed jScrollPane on my website and can't make it work.
My website works as follows: from the main page, pages are loaded dynamically using jQuery's load() method. In the page I load I have the following script to launch jScrollPane:
$(function(){
$('.scroll-pane').jScrollPane();
});
Which seems to be called. No problems so far I guess. The problem is that the page, at the beginning, is not long enough to need a scrollbar. I have hidden content that shows up only on specific actions (i.e. clicking on a button shows the content of a certain paragraph), and when I click to show the content of a hidden div, the scrollbar doesn't appear.
I also tried to call $('.scroll-pane').jScrollPane(); as I show the new content (i.e. in the event that triggers .show() on the hidden div I also call $('.scroll-pane').jScrollPane();) but I had no success with that either.
Can anyone help me?
Thanks
EDIT:
I forgot to mention the structure of the page: I have a div which has class="scroll-pane" and is loaded with the page load and it contains small hidden divs that show up when clicking on particular areas. I would like to add a scroll bar to the div with the class scroll-pane in order to make the content of the showed div scrollable (right now the content stays in the size of the div but it's not scrollable since no jScrollPane scroll bar is shown).
Update:
I tried to put $('.scroll-pane').jScrollPane(); in the callback of the .show() method of my divs and tried to put class="scroll-pane" to those divs that appear, but again nothing is shown (the scroll bar doesn't appear and the div is not scrollable).
Check this demo provided by the developer of the plugin
http://jscrollpane.kelvinluck.com/examples/invisibles.html
When the element is first shown you simply have to (re)initialise the
scrollpane (or you could even use autoReinitialise if you like) and
its width and height will be calculated correctly.
All that you need is
$(function(){
$('.scroll-pane').jScrollPane({autoReinitialise: true});
});
and may be the recent version of the plugin
I suggest to use css visibility property instead auto reinitialising. Each time you call show() method, jScrollPane reinitialises itself. This takes time and has impact on animation.
If you use, say, slide..() methods, then animation starts properly, but scrollable container (and its elements) appears little bit later, and that looks bad.
var wrapper = jQuery('#gallery-album-preview-wrapper');
if (wrapper.css("visibility") == "hidden") {
wrapper.css("visibility", "visible").css("display", "none");
}
if (wrapper.is(":hidden")) {
wrapper.slideDown(1000);
} else {
wrapper.slideUp(1000);
}

Problem adjusting scrollbar after images have been loaded on page

Problem description: I got a page with a table containing text and thumbnails. Usually the table contains more entries than would fit on the screen leading to a scrollbar on the right side. No Problem so far. When loading the page or choosing the next page of the table (pagination) the table gets rendered - the scrollbar is at the bottom of the page where i would like it to be after complete load. Then the thumbnails are getting shown. Due to the fact that they are a bit bigger in size than the text in the table the table gets bigger in heigth leading to the scrollbar being set somewhere in the middle of the page.
Page and table after the images have been loaded, as you can see the scrollbar is somewhere in the middle (vertical) of the page:
I do not want to fiddle around with the thumbnail size. Customers are used to the actual design and image/icon sizes.
Usign the pagination function the table is the only element that gets replaced ont he page. "onload" on tables does not work unfortunatly.
What can i do to have the scrollbar appear after the images have been loaded (leading to the correct placement of the scrollbar)?
Is there a way to set the scrollbar to the bottom of the page after the table has been fully loaded?
There are jQuery plugins to wait for all images to be loaded, but I couldn't get them working on the quick, maybe you can: here and here.
However, you also could use the following hack: watch for the table height and if it changes, scroll to the bottom:
var lastHeight;
function watchTable(){
var currentHeight = $('#myTable').height();
if(currentHeight !== lastHeight){
lastHeight = currentHeight;
$('#myDiv').scrollTop(currentHeight);
}
}
setInterval(watchTable, 100);
see my demo fiddle for a working example.
The best practice is to set the widths of thumbnails in HTML or CSS, if all the thumbnails are of the same size, you can just add the style like
.thumbnail {
width: 150px;
height: 100px;
}
Or, if they size can vary, you must add width and height attributes to the ` tag.
Another solution is to:
Look at the document's scrolltop on DOMload, and look if it's at the bottom, then on onload event (which would be fired when all the images loaded) check again and if scroll to the desired position if needed.
But I recommend always set the dimensions for images, so the page wouldn't jump when they are loaded.
Edit: If you're loading images dynamically, you can do two things:
Preload images and then insert them with the right dimensions.
Use onload for images, however, you still would need to use the document.createElement('img'), so you could be sure that all the images are loaded.
Anyway, in these cases you should use something like that for each image:
var image = document.createElement('img');
image.onload = function () {
// Image is loaded
};
image.src = 'test.jpg';
Note, that you must set .src after attaching the event, or there could be some problems in Opera.

javascript overlay not covering full page when div expands the page height

I realize there's already been several questions like this, but I think my case is a little different.
I have an div that I am absolutely positioning and floating on top of the page, and I'm setting an overlay behind it to grey out the rest of the page. I have it working okay until you scroll up and down the page.
The problem is, when the div appears, it is still populating with ajax data. So the height and width of the bg overlay has already been set, but once all the data loads into the floating div, it sometimes pushing the page down so the height increases. So, I can't calculate the height and width of the window or document because the floating div might not be fully loaded yet, and once it does, it pushes the screen down further, causing the bg overlay to not cover the whole page.
So for example, in the code it's going something like:
loadBoxContent = function(){
..DO AJAX HERE..
..PUT CONTENT INTO FLOATING DIV..
$('#floatDiv').show()
$('#darkOverlay').height($(window).height());
}
I verified this by adding an alert, so that by the time I've clicked the alert, the bg overlay was able to calculate the true page size, and it looks fine.
Sorry, if this sounds confusing but hopefully you get what I'm trying to achieve. I'm assuming this isn't too difficult, but I haven't been able to figure it out.
Any help would be appreciated, I'm using jquery.
Thanks
Overlay ;)
** update, setting position of all corners to 0 instead of using width/height 100% **
$("<div/>")
.css({
position:"fixed", // ze trick
background:"#000",
opacity:.5,
top:0,
bottom: 0,
left:0,
right: 0,
zIndex: 2999 // everything you want on top, gets higher z-index
})
.appendTo("body");
Or put the above css settings in a css stylesheet (opacity needs cross browser hacks).
$("#dark-overlay").show();
Here is the solution :
JQuery Show Loading Plugin
Don't try to invent the wheel !!!
Here is a demo :
Loading Demo
Now you just need to create a main container div for your page and just ask this simple plugin to do it for you.
Maybe you want to read the plugin source and find how it works...

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