Calculating Height of Sidebar Dynamically - javascript

I'm trying to work out the algorithm for a fixed div that grows in height (while scrolling) until it's equal to the height of the viewport or div with fixed position relative to another div and the bottom of the viewport
I am using Twitter Bootstrap affix to lock my secondary navigation bar (yellow) and my sidebar (black) to the top of the screen when the user scrolls that far. 
This works fine. The sidebar is the piece that's giving me trouble.  When it is in its in its starting position (as shown in the diagram belorw), I want the top of the bar to sit 30px
down from the secondary navigation bar (yellow) and 30px up from the bottom of the page. 
As the user scrolls, the bar should grow in height so that it remains 30px beneath the secondary navigation bar and 30px above the bottom of the screen (As shown in the diagram below)
After the bar is fixed position, I am able to do what I need to do.  
.sidebar { 
position:fixed;
top:100px;  
bottom:30px;
left:30px;
}
What I can't figure out is how to position the TOP of the sidebar relative to my
secondary navigation bar and the BOTTOM of my sidebar relative to the bottom
of the screen. I've tried calculating the height of the sidebar at the beginning and the end of the
scroll but this causes issues.
I've also tried calculating the final height of the sidebar and letting the bottom of
the sidebar just run off the edge of the screen (when it's in its initial position), but
if there's not enough content on the right side to warrant scrolling, I have no way
of getting to the bottom items in the scroll bar.  Plus my screen starts bouncing
in a really un­attractive way.
below is the current code in use:
ShelvesSideBar.prototype._resize_sidebar = function(_this) {
var PADDING = 50;
var window_height = $(window).height(),
nav_bar_height = $('.nav_bar').height() + $('.secondary_tabs').height(),
sidebar_height = window_height - nav_bar_height - PADDING,
sidebar_scrollable_height = sidebar_height - $('.bar_top').height();
_this.$container.height(sidebar_height);
_this.$container.find('.bar_bottom').height(sidebar_scrollable_height);
/* reset the nanoscroller */
_this.$container.nanoScroller();
};
   
this code is called on page load and again on window resize. Any help would be greatly appreciated!

I've been trying to do something similar (minus the fixed elements and navbars). What I found was in order to do any sort of relative height scaling every element above the element I wished to scale all the way up to the opening html tags had to have a relative height set, even if it was just height:100%;. (here's my original question Variable height, scrollable div, contents floating)
My goal was to have the body height fixed to window size like a native full screen application would be with my content subareas scrolling, so this is a bit off topic for what you're wanting to accomplish. But I tried using JS/JQ to start off with as you're trying to do currently and found that I simply couldn't get the window height because the default behaviour for height management is to expand the page height until everything on the page fits. And all the getHeight methods I tried we're getting the page height not window/viewport height as promised. So you may wish to try fixing your body's height to the window and going from there using overflow:scroll; to scroll the page.
A quick note on overflow:scroll; if you have users who use WP8 IE (and probably other versions of IE) it may be advantageous to implement FTscroller to handle all your scroll elements as the overflow property defaults to hidden and is a fixed browser property. The only problem with FTscroller is because it uses CSS offsets to move the content container it may wreak havoc on elements that are designed to switched to fix when they reach x height from top of page because technically the top of page (or rather the top of the container they're in) isn't at the top of the page anymore it's beyond it. Just something to be aware of if you do need to cater for this browser.
And apologies for the complexity of my sentence structure. :/

so I was able to figure this out, for anyone still looking. What I ended up doing was binding to the window scroll event and - whenever the scroll occurred - I check if the class "affix" has been added to the sidebar. If it has, then I perform one set of calculations to determine sidebar height. Otherwise, I perform the other set of calculations. Code below:
/* called on window scroll */
var PADDING = 70;
var window_height = $(window).height(),
nav_bar_height = $('.nav_bar').height() + $('.secondary_tabs').height(),
header_height = $('.prof_block').height() - nav_bar_height,
sidebar_height = _this.$container.hasClass("affix") ? window_height - nav_bar_height - PADDING : window_height - (header_height + nav_bar_height) - PADDING,
sidebar_scrollable_height = sidebar_height - $('.bar_top').height();
_this.$container.height(sidebar_height);
_this.$container.find('.bar_bottom').height(sidebar_scrollable_height);

Related

Retrieving viewport height of screen in mobile browsers with jquery

I'm attempting to get the viewport height in mobile browsers WITHOUT the height of the browser bar but all of the solutions I've attempted have come up short.
What others have suggested is using the below, however it does not work for me. I still get a blank white bar at the bottom of the window when scrolling
var screenHeight = window.innerHeight;
$('.mobile-nav-wrapper').height(screenHeight)
I believe what you are looking for is scrollHeight
The scrollHeight property returns the entire height of an element in
pixels, including padding, but not the border, scrollbar or margin.
You can try this:
document.body.scrollHeight
Solution 1:
I don't have an answer using jQuery. But using a plain/vanilla JavaScript wouldn't cause any issue :).
Following script allows you to detect the Viewport size (height and width) reliably.
https://github.com/tysonmatanich/viewportSize
Sample usage:
<script type="text/javascript">
var width = viewportSize.getWidth();
var height = viewportSize.getHeight();
</script>
I have used it in couple of projects, were i have to re-initialize some widgets based on current Viewport width/height rather than using window width/height (Window width/height calculation isn't consistent in all browsers - some include scroll bar size 16px as a part of window width and some doesn't).
Sample Test page:
http://tysonmatanich.github.io/viewportSize/
Solution 2: (Just for reference - Not an answer to OP's question, though it is related so I thought that it can remain)
Well modernizr has a very good addition Modernizr.Mq. Through which you can cross check which break point range you are in...
if(Modernizr.mq("(min-width:320px)")){
//Do job 1
}
else if (Modernizr.mq("(min-width:768px)")){
//Do job 2
}
or
based on height
Modernizr.mq("(min-height: 800px)")
http://tysonmatanich.github.io/viewportSize/

How to get the actual width available for content on the browser window?

I'm positioning my elements using JavaScript. In order to do it perfectly I have to get the amount of horizontal space available. Badly, $(window).width() does not take in account the scrollbar width. The result is this:
bad http://dl.dropbox.com/u/62862049/Screenshots/fb.png
Here, "Pagina 1" is contained in a small div that was supposed to align with the right border of the window. Well, it does - literally - ignoring the scrollbar, which covers part of the div, throwing the "1" of "Página 1" to the next line.
use this function
function scrollbar_width() {
var calculation_content = $('<div style="width:50px;height:50px;overflow:hidden;position:absolute;top:-200px;left:-200px;"><div style="height:100px;"></div>');
jQuery('body').append(calculation_content);
var width_one = jQuery('div', calculation_content).innerWidth();
calculation_content.css('overflow-y', 'scroll');
var width_two = jQuery('div', calculation_content).innerWidth();
jQuery(calculation_content).remove();
return (width_one - width_two);
}
now calculate available with
var availableWidth = $(window).width() - scrollbar_width();
This is similar to two previous questions:
how to get innerWidth of an element in jquery WITHOUT scrollbar
and
How to get screen width without (minus) scrollbar?

Adjusting window scroll position in JavaScript to counteract element's resizing above

I'm trying to counteract an adjustment to the height of an element which is above the scroll offset by calculating the difference in height and then updating the current scroll position to account for it.
The problem is that there's no way that I can prevent a very quick flickering artefact. Whether I adjust the element's height and then the scroll position, or vice versa, I can't seem to prevent a quick visual jump.
Does anyone know how this could be overcome? I want these to operations to happen at the same time with no rendering in-between but I'm not sure if it's possible.
// Setup
...
var myElement = ...
var oldHeight = ...
var scrollOffset = window.scrollY;
var newHeight = 100;
var diff = newHeight - oldHeight;
// Determine if we need to counteract new size
var adjustScroll = (absoluteOffset(myElement) < scrollOffset);
// Adjust size
myElement.style.height = newHeight+'px';
// Adjust scroll to counteract the new height
if (adjustScroll) window.scrollTo(0, scrollOffset+diff);
I'm working with WebKit, specifically on iOS.
for webkit you can use CSS transitions/animations to smooth this but it's still sound like you are going the wrong way to begin with. I am sure that whatever is it you are trying to do can be solved purely with CSS (maybe with some very minimal Javaqscript). Post an example of you HTML + CSS + JS.
You could use scrollIntoView with timers to simulate multiple threads.
Or you could do it inside a document fragment beforehand.
Sorry to be reviving an old post here, but i came across this looking for a solution to a similar problem to do with browser resizing.
Stackoverflow user James Kyle created this little jsfiddle using jQuery that attempts to maintain scroll position as best as possible when a page is resized
var html = $('html'),
H = html.outerHeight(true),
S = $(window).scrollTop(),
P = S/H;
$(window).scroll(function() {
S = $(window).scrollTop();
P = S/H;
});
$(window).resize(function() {
H = html.outerHeight(true);
$(window).scrollTop(P*H);
});
http://jsfiddle.net/JamesKyle/RmNap/
you could try using this same code and trigger a 'resize' event on the html when the image has loaded by using a jQuery library like imagesLoaded

jquery (or js general) splitter with dynamic height

There are some ready JavaScript (jQuery) splitters, but they require panels height to be set. The problem is, that my website doesn't support fixed height, it just can't. Other thing is that this container can change it's height dynamicly, so I'd like to this splitter to adjust to the panels height.
Is there a script or a way to avoid that?
My idea was to set container's height the bigger panel's height, like:
var lheight = $("#LeftPanel").height();
var rheight = $("#RightPanel").height();
if(lheight > rheight){
$("#container").css("height", lheight+"px");
} else {
$("#container").css("height", rheight+"px");
}
but this doesn't seems to be a nice way for me.
Do you have any suggestions?
You can pass a new value to .height(), like this:
var h = Math.max($("#LeftPanel").height(), $("#RightPanel").height());
$("#container").height(h);
In this case we're just using Math.max() to get the taller one, and setting the height to that.

A bit of problem with implementing a modal dialog

I am developing a modal dialog as a part of a web application. There is one thing that's been of a puzzle to me. Please watch a movie clip that I just uploded at http://inter.freetzi.com/example/. I feel strongly that I have to accompany my question with a video because this is the case when it's better to see once, than to hear 100 times.
(It could be vertical scrolling, or both vertical and horizontal at the same time. But I am using horizontal scrolling in my example, so watch for it.)
Here's about my question:
Width of the transparent mask affects the width of the page itself. But in Opera, for exemple, every time the window gets resized, the page gets width that is at most close to 'true'. While in IE, once the transparent mask has affected the width, afterwards the page remembers it and stays with it. What is the problem and how to settle it? How to make IE behave the way Opera does?
In my project, I do the following:
//curViewpointW and curViewpointH are current width and height of the viewpoint (current is meant to be the moment of the resize event)
oMask.style.width = curViewpointW + 'px';
oMask.style.height = curViewpointH + 'px';
var pageWH = getPageWH(); //getPageWH() is a function that gets current width and height of the page (with scrolling if there is any)
var curPageW = pageWH[0];
var curPageH = pageWH[1];
if (curPageW > curViewpointW) {
oMask.style.width = curPageW + 'px';
}
if (curPageH > curViewpointH) {
oMask.style.height = curPageH + 'px';
}
But IE ignores that somehow...
P.S. It's jQuery in my example, so many of you may have used its dialog before.
Have you looked into setting an onresize event handler that will adjust your mask dimensions when the window is resized? If you are using Prototype, you can set up such a handler unobtrusively like this:
Event.observe(document.onresize ? document : window, "resize", function() {//dostuff});
courtesy of the Roberto Cosenza blog

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