Develop Reference

How to Dynamically Update outerHeight of An Element When Another Element Changes in Height on Window Resize?

Bit of a jquery / javascript noob question here. I have a subnav element that I am sticking to the bottom of my primary nav once someone hits a certain scroll point. To do that, I'm offsetting the subnav element by the height of the main nav element, as shown below.
$(function() {
$('.sticky-nav').stickybits({
useStickyClasses: true,
stickyBitStickyOffset: $('.navbar-fixed-top').outerHeight(),
});
});
The problem that I'm running into is '.navbar-fixed-top' has a different height at mobile / tablet and desktop sizes (the height changes at 992px) and the offset gets messed up if someone resizes the screen (i.e., if they start at desktop, and then resize to mobile / tablet, there's too much space above the subnav because the main nav was taller in desktop).
My question is, how can I update the code above to dynamically update the outerHeight when the height of the .navbar-fixed-top element changes?
I tried the code below, inspired by the answer to this question: Resize element width on window resize jquery, but it's not working
$(function() {
var topNavHeight = $('.navbar-fixed-top').outerHeight();
$(window).on('resize', function(event) {
var topNavHeight = $('.navbar-fixed-top').outerHeight();
});
$('.sticky-nav').stickybits({
useStickyClasses: true,
stickyBitStickyOffset: topNavHeight,
});
});
Thanks!

I think this will work:
$(function() {
let stickything;
function set_sticky() {
if (stickything) {
stickything.cleanup();
}
stickything = $('.sticky-nav').stickybits({
useStickyClasses: true,
stickyBitStickyOffset: $('.navbar-fixed-top').outerHeight(),
});
}
$(window).on('resize', set_sticky);
set_sticky();
});
Just changing a variable isn't enough, you have to tell stickbits to update. There doesn't seem be a way to update the offset so this just reinitializes it.

Trigger jQuery function at specific different browser widths

So I have this jQuery function that adds margin-top to an element based on the height of another element.
I'm trying to have this function trigger again on window resizes. (Preferably 1200px, 991px, 768px, 500px breakpoints)
If there is a good solution that allows the function to trigger with any browser resize, even better. I just need to make sure this wont cause "lag" or "slowness" due to the function triggering 100 times during a resize event for example.
Here is a codepenn with my current function:
http://codepen.io/bruno-gomes/pen/vgRbBB
Code:
jQuery(document).ready(function($) {
(function() {
var navBarHeight = $('.header').height();
$('.content').css('margin-top', navBarHeight);
})();
});
The idea is that I want the fixed header to not cover the content, and the size of the header will vary depending on the width of the browser. This becomes an issue when user resizes browser because the function is only triggering once on load.
I have the IIFE setup like that because it's a Joomla site and they don't work properly otherwise by the way.

You can use .resize() for that

Ok seems like this approach solved all my problems ^.^
jQuery(document).ready(function($) {
var height = $('.header').height();
resizeHeader(height);
$(window).resize(function() {
var height = $('.header').height();
resizeHeader(height);
});
function resizeHeader(height) {
$('.content').css('margin-top', height);
}
});

Change Image when Browser Window is Resized

I have a slideshow on my home page that uses images in a landscape orientation. However, when the browser is resized, the images eventually get clipped. To prevent this, I want to swap the landscape-oriented images to square ones when the browser reaches a certain pixel width. But it must switch back when expanded again. How would I go about this?

jQuery provides this resize event, And you can use it like,
$(function() {
$(window).resize(function() {
var width = $(window).width();
var height = $(window).height();
$('yourimage').attr('src', toAnotherSource);
// or you can do anything with the image here.
});
});

iPad canvas rotation

I created a canvas element and I'm using javascript to make it as big as possible in the viewport, while maintaining the aspect ratio.
When you rotate the iPad, the device first rotates the page and only after that launches the resize event.
The problem is, if you come from landscape (about 800px wide) to portrait (about 400px), a part of the body is not being displayed, because the resize didn't happen yet at that moment. After this, the resize event resizes the canvas to the correct size, but then a part of the canvas (& document) is still outside the viewport.
So basically the problem exists because the resize event only launches after the iPad already cut off a part of the body on both sides because the body is too wide.
I could fix this by setting a margin to the canvas to compensate, but it's a dirty solution... does anyone have a better suggestion?

This could also be considered a dirty solution, but in the past I have used a setTimeout to deal with this issue, and it seems to always be reliable.
window.onorientationchange = function() {
canvasResize();
}
function canvasResize() {
window.setTimeout(function () {
//Your code here based on new size
}, 100);
}
Or if you are looking for a slightly less dirty solution, you should be able to just keep track of the viewport width yourself, and then wait until that changes to do your updates. Add to your script somewhere:
var viewportWidth = window.innerWidth;
And change canvasResize:
function canvasResize() {
if(window.innerWidth != viewportWidth) {//Dimensions have changed for sure
viewportWidth = window.innerWidth; //Update viewportWidth for future use
//Your code here based on new size
}
else {
//Delay and try again
window.setTimeout(function () {
canvasResize();
}, 100);
}
}
Both of are pretty quick and dirty, and I'd be interested if there's a more elegant solution, but I haven't found one yet.

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