Develop Reference

Get Div Location with Responsive Layout

I have a div on a page that acts as an overlay for the entire page when a button is pressed. Here is the problem I'm having:
When the overlay is showing, I am using Javascript to position the overlay starting at the top of a div on a page using the following method:
var elementTop = $("#myVideo").offset().top;
$('#lightBoxBackground').css('top', elementTop);
However, when I change the size of the page, rather than dynamically getting the new position of the myVideo div, it seems like it keeps the original position. So, as I expand my page, the overlay div stays where it was opened rather than constantly moving with the myVideo div.
Is there a way to dynamically continue getting the new position of a div as the page layout changes using html, css, and javascript so that way my overlay div moves with the myVideo div? I'm new to JavaScript and have checked through a lot of questions, but haven't found anything useful.
Thanks for any help.

Using javascript you could listen for width/height changes on the window with .resize()
$(window).resize(function() {
//resize just happened, update your positioning values
});
Note: This solution uses jQuery - https://api.jquery.com/resize/

creating a visible on load Pre-loader Page

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.

scroll to top of newly generated div

So in my site, when a button is clicked,I dynamically generate a div, which contains a grid of images. It goes like this:
$('.prod-images').click(function(){
var prodImages = generateProdImagesGrid(this);
$('#prod-images-grid').html(prodImages).show();
});
This works fine. And I have another button which will close this div on click.
Now this div can be taller than the screen and require vertical scrolling. The problem is that because of all the CSS/styles in this page, this div always opens only at the scroll position where it was closed. So when I open it first time, it is scrolled to the top and everything is fine. Now, suppose I scroll this div halfway down and then close it. Next time when it is opened, it opens at that scroll position.
I tried doing:
$('#prod-images-grid').html(prodImages).scrollTop(0).show();
This does not work (at least in chrome) because the div is not fully rendered when the scrollTop() call is executed.
The only way I can make this work is to give a long delay between the div rendering and the scrollTop call like so:
$('#prod-images-grid').html(prodImages).show();
window.setTimeout(function(){
$('#prod-images-grid').scrollTop(0);
},10000); //call scrollTop after 10 seconds
As you can imagine, this is not at all a good solution. Does anyone have any suggestions on how I can render the div so that when its visible, it is scroll to its top position?

Doing:
$('#prod-images-grid').html(prodImages).scrollTop(0).show();
means that it's the <div id="prod-images-grid"> which gets scrolled; since this div has no content, it cannot be scrolled.
Rather do:
$(document).scrollTop(0);
$('#prod-images-grid').html(prodImages).show();
The 0 argument of scrollTop can of course be modified to point to the position of the document where you want your dynamically generated div to show.

You can handle a function after the contents is showing whith this propety of .show():
$( ".target" ).show(interval, handler);
Like this:
$('#prod-images-grid').html(prodImages).show(1, function() {
$('#prod-images-grid').scrollTop(0);
});
(you can change 1 for any other value)

Correct way to reset jScrollPane viewport position

I've been looking around for answers and everything I apply to my own code doesn't seem to work. I have a DIV with content. When I click on a link the DIV fades out, the content changes via the jQuery .html event and then the DIV fades back in. This gives the illusion of a gentle page change on my site. This DIV has a jScrollPane which works fine before any links are pressed.
What is happening however is that the scroll pane 'draggable area' stays the same size when the content is re-written and there is more or less, or even if there is no need for one at all.
I need to get the scroll pane 'draggable area' to change size in relation to the new content and I need it to scroll back to the top inbetween the .fadeTo fade out and in effect.
I've tried some of the following:
function showhome() {
$('#infohome').stop(true,true).fadeTo(100,0)
$('#infohome').delay(100).html("NEW CONTENT")
$('#infohome').stop(true,true).delay(200).fadeTo(100,1)
refreshNav();
function refreshNav() {
var element = $('.scroll-pane').jScrollPane({scrollToY(0, animate)});
var api = element.data('jsp');
}
As well as:
myJScrollPane.getVerticalScrollbar().setValue(int Pos);
and a few others.
As always, any help would be greatly appreciated.

HTML/CSS/JAVASCRIPT : How to move an element and not show scrollbars

i'm trying to slide a div element from outside the page to within the page. However as soon as the element is shown outside the page, horizontal scrollbars appear!
How can I achieve this without the scrollbars appearing?
Any help appreciated very muchly, thanks :)

Briefly, using overflow-x:
function moveStuff() {
$('body').css('overflow-x', 'hidden');
$('#iteminmotion').show().animate(..., function() {
$('body').css('overflow-x', 'auto');
});
}

move the element off the page to the left, moving it off to the right increases the width of the page

You could temporarily turn off side scrolling by applying this css to the body:
body {overflow-x:hidden;}
http://jsfiddle.net/pxfunc/YYUZJ/

Do you really need to construct the element off page, or just make it look like it slides onto the screen? Ive done similar things in the past to emulate a graphic that slides across a page, but instead of starting outside the view area I've created it as far to the side as possible and then animated the slide to the middle. The user experience at that point can be a graphic that slides onto a page from outside the view area.