Develop Reference

jquery resize so content is always centered perfectly

I have the following right now, but its not perfect:
$(window).resize(function () {
$("#app-views").height($(window).height() - 140);
});
Basically, I have 75px from top before my content starts, and I have 60px from bottom of the page to my content.
How do I make it so when I resize the window, it will always respect those dimensions? I am using malihu scroll bar, and I am loading my view into #app-views.
I have a border all around the window (10px), a navbar (50px), and 15px of padding until my body. Then, I have 15px bottom padding on body, a footer of height 35px, and 10 px bottom border.
Here is the basic HTML:

If you want your contents to be placed and resized while keeping the same distance from the top and the bottom of the window, you don't have to use jQuery or Javascript. Only CSS would do the trick. Try this without height attribute in your style code:
#app-views {
position: fixed;
top: 75px;
bottom: 60px
}
You can set left and right without width to get the same effect in horizontal dimension.

You say you have specific measurements to place your content on the page
(75px from top before my content starts, and I have 60px from bottom
of the page)
Well with jQuery offset you can get the top position of the element and you can also update the css top position on screen resize so that your content will always adjust its position on resize.
To see where the bottom of your content element is you could find the offset of the top of the content and add the content's height to get the bottom position of the content relative to the top of the page.

I would recommend doing this in CSS, perhaps by dynamically changing the jQuery object's CSS property. I would attend to it with a simple CSS selector. This works even when the window is resized. Have a look:
#app-views {
position: absolute; /*this will allow you to position it exactly where you want it*/
left: 50%; /*this will move the left side of the container halfway across the page*/
transform: translateX(-50%); /*moves the container left by half its width,
so that the centre of the container aligns with the center of the page*/
}
You can adjust the vertical position with the 'top' property and 'translateY()' in a similar way I demonstrated with transform and translateX().
If you want to use jQuery, you could try:
#('app-views').css('position', 'top');
Furthermore, I would also suggest that you do not maintain the 75px at the top of your page for all kinds of screen sizes. 75px may be suitable for a desktop but not for a mobile. If you do intend to make your website fully support mobile, it is often a good idea to design the mobile layout first, as it tends to by simpler. Then, you can use media queries to adjust it for the desktop. It really does work brilliantly. I've used it myself many times before. You can learn more about that here:
MediaQuery CSS

Center div vertically or affix to top of window if height is too great

I have a popup that's centered on my page using the following syntax:
position:absolute;
top: 50% !important;
left: 50% !important;
transform: translate(-50%,-38%); //well, slightly lower than center...
This works very well - unless the height of my popup is greater than the height of my current window. It doesn't happen often, but when it does, I can scroll DOWN to see the additional content, but I cannot scroll UP any further than the top of the window to see what's above, like in this example:
I want to say vertically center, but if the height of the div would cause the top of it to not be displayed, just affix the div to the top of the window instead
What code would I add into this to achieve that?
This is similar to another post on SO:
How to center an element vertically in css in a scrollable container
I'm not looking to center the item with a flex container however. I actually cannot use flex in this instance, because the div is a result of a javascript plugin and I can't add a separate parent div outside of this without a LOT of work. I am looking to center UNLESS the height of the div is too great - then i want it to affix itself to the top of the window.
If I could place some sort of div above this popup div that has a height of 1px and force the popup div never to go higher than it, that would be fine as well. I have a very specific reason for why I want the div at the TOP of the window when it's very long - I don't want it centered 100% of the time (which is what the other post does.)
I've also tried using a pseudo-element like so:
.popUpBody::before {
content: " ";
height:50px; //this needs to be dynamic based on the height of the parent
width:100%px;
display:block;
}
as it moves the rest of the div down - but I'd need to find some way to use a dynamic height - it might be 300px, or it might be 5000px. This also doesn't seem like a very good way to do this.
I could make it so the height of popup div is always centered by taking out the second transform variable: transform: translate(-50%); - and this would be a last resort, but I would really like for the div to affix to the top of the window when its height is larger than the window itself - if this is possible.
Javascript/Jquery is fine if I need to use that to add dynamics.

fix div when window resize

I have a div that has fixed position and bottom 0 to display at the bottom of the window.
My problem is when window resize, this div move to up and into other elements. For example when I open console box in chrome this div jump to other elements in facebook fix position such as friend list, when I open console box, element jump to up but hidden up element.
Please help me how I can fix div in window resize.

CSS Position Fixed:
Do not leave space for the element. Instead, position it at a
specified position relative to the screen's viewport and doesn't move
when scrolled. When printing, position it at that fixed position on
every page. Fixed positioning is similar to absolute positioning, with
the exception that the element's containing block is the viewport.
This is often used to create a floating element that stays in the same
position even after scrolling the page. - by Mozilla MDN
In other words, When you use position: fixed; that takes elements out of the document's regular flow.
How I can fix div in Window Re-size?
Solution: There's no way to do it as you want using CSS. You must remove position: fixed; because when you set bottom: 0px with position: fixed; to your element then it doesn't matter that what is the size (vertical) of your browser or window because position: fixed; element will always appear on the bottom of the viewport screen at 0px.

You can use
position: fixed
or
`position:absolute`

Hiding an element with hide() causes a page "jump"

I'm trying to create an effect where I display a big logo on page load. When the user scrolls pass the logo and navigation, I want to display a fixed nav bar with a smaller logo. I then want to hide the big logo so that when the user scrolls to the top they still see the fixed nav bar (i.e. the big logo and original navigation stay hidden).
However, when I remove a big block element with the .hide() property it causes the page to "jump" as the display:none property gets set. This reduces the usability of the page, as the location jumps the size of the element that was removed, potentially confusing users.
Is there a way I can get the effect I want, while still providing a smooth experience to the user? I've been thinking of potential options, but have been drawing blanks. Hoping you guys can inspire me :)
A simple JS fiddle can be seen here: http://jsfiddle.net/darudude/vA5WG/ (Note: You'll have to increase the result section to 720+px to get it to work properly - I'm still working on the responsive part)
The code in question:
function UpdateTableHeaders() {
var menu = $(".main_nav_menu"),
offset_top = menu.offset().top;
var scrollTop = $(window).scrollTop();
if (scrollTop > (offset_top + menu.height()))
{
$(".clone").addClass("floating_header");
$(".big_logo").hide();
}
}
$(window).scroll(function(){
UpdateTableHeaders();
});

You can try this ,
Add a new style
<style>
.hide {
position: absolute !important;
top: -9999px !important;
left: -9999px !important;
}
</style>
And change your JS to
$(".big_logo").addClass('hide');
Instead of
$(".big_logo").hide();

Use visibility:hidden then
$(".big_logo").css('visibility','hidden');

Maybe it is because a different browser - margin/padding thing. Have you tried to add this to the body element (or to the container element if it inherits some margins/paddings)
body{
margin:0;
padding:0;
width:100%;
}

Move loading div down as ajax content loads

The form I am creating for a mobile website shows new fields based on previous selections. i.e. - a user selects and option from a dropdown menu (a date) and then a series of times shows up based on the day selected. The times are not showing until the day is selected.
I have a spinning loading div while the times are loaded in the background via ajax. The problem I am having is that the loading div sits at the top of the page when the 'action' is taking place about three-quarters of the way down. This 'action' part is in the viewport (it's a mobile website) and the loading div is at the top of the page - which is far above the users viewport.
How can I bring the loading div down so that it's always in the current viewport? How can I make the loading div follow the place in the form where the user currently is taking into account scrollbars?
I have been trying to use the vertically centred html/CSS model as described here:
http://www.jakpsatweb.cz/css/css-vertical-center-solution.html
But it is not working and the centre of the page doesn't seem to update at each event when a form element is clicked. I think I need to use the focus or blur event for the form field to update this and reassess, but I don't seem to be able to get it working.
Does anyone have any tips on how to move the loading div to the centre of the current viewport area each time the page increases in length?

If your loading div is designed to be inside the document flow - e.g. a new content block inside the form - it's best to use jQuery to insert the loading div inside the content itself. It will be very difficult to position it pixel-perfect otherwise.
If the loading div is to appear as an overlay to the document then you can use fixed CSS positioning with a high z-index. To center it on all screen resolutions use jQuery and the formula (window.height() - div.height())/2 as the top pixel position. The code will be similar to this answer.
Hope that helps

If you do something like this, and put the div inside your <body> tag, it will stay in the middle of the visible area.
div.loading {
position: fixed;
top: 47%;
left: 47%;
height: 6%;
width: 6%;
z-index: 1000;
}
Another solution is to put it at the end of the container content will be loading into. Just make sure to load the content before it. If you give it a margin:auto; it'll stay right in the middle and keep pushing down.
EDIT: It's also worth noting the answer here. This will prevent covering up something important in a way the user can't fix.

Set your loading div's position to fixed, this will of course cause it to escape from its parent in the DOM structure, you will then need to position it where you want it. Fixed positioning is relative to the visible area of the viewport.
<html>
<head>
<style type="text/css">
#loader {
height: 30px;
position: fixed;
top: 50%;
left: 50%;
background: #ccc;
}
</style>
</head>
<body>
<div id="loader">Loading...</div>
</body>
</html>
This will result in the loader div always being centered on the screen, no matter where the user has scrolled, left/right up/down.