Develop Reference

Want to change sticky sub nav position on window resize depending on header height

I'm very unfamiliar and still learning javascript/jQuery and I'm having trouble putting together the syntax to change a secondary navigation bar offset position to stick to a header that adjusts its size when the screen size changes (logo is setup to viewpoint percentage, hence its height varies with screen size).
So far I got the first part of the following script to calculate the header outerHeight and it works on any screen size but only on the first page load (not while resizing in real time).
jQuery(document).ready(function resizeHeader ($){
$('#CPOP-header').each(function(){
$('#CPOP-sticky-sub-menu').css({
'top' : $(this).outerHeight(true) + 'px'});
});
$(function() {
$(window).on('resize',resizeHeader);
alert($('#CPOP-header').outerHeight(true)+'px'); // works on first page load only, will remove later
});
});
However, I want it to "monitor" browser window resize dynamically to avoid browser refresh but I can't figure out how to bind or merge the second part on the same script since I'm not very familiar with javascript/jQuery:
$(function() {
$(window).on('resize',resizeHeader);
alert($('#CPOP-header').outerHeight(true)+'px'); // works on first page load only, will remove later
});
This is for a WordPress/Elementor website, the code will be inserted in an HTML widget.
Any help will be much appreciated!

if anyone is looking for something similar, here it is
const $ = jQuery;
function resizeHeader () {
$('#CPOP-header').each(function(){
$('#CPOP-sticky-sub-menu')
.css({'top' : $(this).outerHeight(true) + 'px'})
});
}
jQuery(document).ready(resizeHeader);
$(window).on('resize',resizeHeader);
Thank you to u/toi80QC at reddit for taking the time and giving a hand!

How can I control an image's size

I am a skilled database / application programmer for the PC. I am also an ignorant html / javascript / web programmer.
I am creating some documentation about some .Net assemblies for our intranet. Ideally I would like to display an image full size if the browser window can fit it. If not then I would like to reduce it and toggle between a small version and full size version by a click. It is a dependency chart and can be different sizes for different pages. I would prefer a single function to handle this but being it is for our use none of the requirements I mentioned is set in stone. I would like to make it work well but nothing is mandatory.
I read a lot of stuff but couldn't find anything that matched what I wanted. First I tried this (after a few iterations):
<img src='Dependancy Charts/RotairAORFQ.png' width='100%' onclick='this.src="Dependancy Charts/RotairAORFQ.png";this.width=this.naturalWidth;this.height=this.naturalHeight;' ondblclick='this.src="Dependancy Charts/RotairAORFQ.png";this.width="100%";'>
It has problems. First off it enlarges a small image and it looks funny. Second I would have to put the code in every page. Third it requires a double click to restore it. I was going to live with those short commings but the double click fails. I can't figure out how to restore it.
So I tried to get fancy. I couldn't figure out how to get past problem 1, but solved 2 and 3 by creating a function in a separate file. Then I ran into what appeared to be the same problem. This was my second attempt:
function ImageToggle(Image)
{
if (ImageToggle.FullSize == 'undefined')
ImageToggle.FullSize = false;
if (ImageToggle.FullSize)
{
Image.width='100%';
ImageToggle.FullSize = false;
}
else
{
Image.width=Image.naturalWidth;
ImageToggle.FullSize = true;
}
return 0
}
And in my page:
<img src='Dependancy Charts/RotairAORFQ.png' width='100%' onclick='ImageToggle(this)'>
Can what I want be done? It doesn't sound impossible. If it is a large amount of effort would be required then alternate suggestions are acceptable.

You're probably interested in the max-width: 100% CSS property, rather than a flat-out width:100%. If you have a tiny image, it'll stay tiny. If you have a huge image, it gets resized to the width of the containing element.
For example: http://jsbin.com/kabepo/1/edit uses a small and a huge image, both with max-width:100%. As you can see, the small image is untouched, the huge image is resized to something sensible.

I would recommend that you set a the max-width: 100% CSS property for the image.
This will prevent the image's width from expanding to be greater than the container's width.
You can also do the same with max-height: 100% if you are having problems with the image overflowing vertically.
Please see this JSFiddle for an example.
(Note: If you set both a width and a height attribute on the <img> tag directly or in your CSS file your image will not be scaled proportionally.)

Does it have to be a toggle or would a mouseover work for you as well?
<style>
.FullSize { width:100px; height:auto; }
.FullSize:hover { width:90%; height:auto; }
</style>
<img src="Dependancy Charts/RotairAORFQ.png" class="FullSize">
Note: when image is made larger IN the page - the surrounding content will be displaced around it - depending on how you have set up the layout.
Also if you have any body margins or table or div paddings, using image width at 100% will make the page scroll. To check just change 90% to 100% and work your way up / down.
You could also force the image to be a specific size until the browser gets made smaller by the user / has a smaller resolution.
<style>
.FullSize {width:1000px;max-width:100%;height:auto;}
</style>
<img src="Dependancy Charts/RotairAORFQ.png" class="FullSize">
A tip: the image used must be the largest one. So minimum width of lets say 1200 pixels wide (if that is the forced image size you use). That way regardless of size it is it will remain clearer than a small image becoming a large. Since it's an intranet, file size shouldn't be an issue.

Thanks all for your help. Rob and Mike both pointed me to an excellent solution. I now have my page load with an image that fits the browser window, resizes with the browser and if the user is interested they can expand the image and scrollbars appear if necessary. I got this to work in a function so minimal code is needed for each page.
To load the image:
<p style="overflow:auto;">
<img src='Dependancy Charts/RotairAORFQ.png' width="100%" onclick='ImageToggle(this)'>
</p>
And the function:
function ImageToggle(Image)
{
if (ImageToggle.FullSize == 'undefined')
ImageToggle.FullSize = false;
if (ImageToggle.FullSize)
{
Image.style="max-width: 100%";
ImageToggle.FullSize = false;
}
else
{
Image.style="max-width: none";
Image.width=Image.naturalWidth;
ImageToggle.FullSize = true;
}
return 1
}

if you want to get current browser window size and if you want to do it on a click event so try this in jquery or javascript:
<script>
$("#myButton").click(function(){
var x = window.innerHeight; // put current window size in x (ie. 400)
});
</script>

Why aren't my elements correctly sized when the page loads?

I'm trying to get a navigation to hide if there isn't enough room in the window. The navigation is contained in a wrapper that also contains a logo, and so to calculate if there is enough room I use the following:
if ($(window).width() < ($('#logo').outerWidth() + $('#nav').outerWidth()))
$('#nav').hide();
I have that run when the document is ready and when the window is resized. What I noticed was if the window started off too small it wasn't hiding the nav so I looked into it further. What I found is the nav width that is being calculated when the document is ready is incorrect.
The nav consists of and they are all calculated to be about 3-4px too small, but when resizing the window the values get correctly calculated. Does anyone know why this might be?

It could be that some images haven't fully loaded when the function is called. Try binding the event to;
$(window).load();
instead of;
$(document).ready();
This will make the function run after the page has completely finished loading, including images whereas $(document).ready() only waits for the DOM to load.
$(window).load(function () {
if ($(window).width() < ($('#logo').outerWidth() + $('#nav').outerWidth()))
$('#nav').hide();
});
As Terry pointed out, on a very resource heavy site this would result in a large delay before hiding the nav bar which could be a problem, so you could instead check the status of the #nav or #logo element's load.
$('#nav').load(function () {
if ($(window).width() < ($('#logo').outerWidth() + $('#nav').outerWidth()))
$('#nav').hide();
});

The problem typically comes from the fact that the browser is still computing the size of the elements when you call your line of code.
Try to keep an eye on what sizes you are changing in your $(document).ready() function (would have been good to paste the whole code here...). Any change to the size of an element could affect all others.

Use plain javascript rather then Jquery

I am attempting to code the game breakout in javascript. Currently I have it working using JQuery in several locations. My professor does not want the class to use Jquery so I have to change the areas I use jquery to javascript.
function windowsize() {
WIDTH = $("#canvas")[0].width = ($(window).width()-20.5);
HEIGHT = $("#canvas")[0].height = ($(window).height()-20.5);
}
windowsize();
I am using this function to get reference to the canvas element and subtracting from the sides to remove the scrollbar. (on a side note if anyone knows how to remove the scroll bar without subtracting let me know!)
I attemped the following code to get reference to the canvas, but cannot get it to work?
var c=document.getElementById("canvas");
var ctx=c.getContext("2d");
Here is my fiddle: http://jsfiddle.net/Kinetic915/kURvf/29/
Any help is appreciated!
Thanks!

Assuming Chrome, document.documentElement.clientWidth seems to do it for you. Or, find a 100% width element on the page and get the width of that.

div max-height set dynamically using javascript

I have a web app using master page and content pages (see the attached image). I need to set max-width of one div in content page dynamically accordint to the browser window size (so that the whole app stays on the page, without scrolling). I couldn't find the sloution (or couldn't replicate the results) using just html and CSS. So I'm thinking to do it using javascript. But the problem is, I NEVER used it, so I really have no clue how to do it. I'd really appriciate if someone took a couple of minutes and write the function that will do it. As I see it, I should take difference in height between bottom edge of the header and top edge of the footer and subtract height values of searchbar and button bar.
EDIT:
Thanks to maxedison for providing that code. But, how do I use it? :D I'm a total noob. I have a problem, since I use masterpage and content pages. Where do I put that code?
EDIT 2 - THE ANSWER:
I looked a little further into how to use jQuery, and searched here some more, and I found a solution. Next time I start developing an application, I'll use jQuery from the bottoms up...It just simplifies some things so much. :)
So for the solution: It's similar to what maxedison suggested, but I changed it so, that I set height with CSS and I just added a fixed value to deduct from window.height.
<script type='text/javascript'>
$(function () {
$('.myStyle').css({ 'height': (($(window).height()) - 350) + 'px' });
$(window).resize(function () {
$('.myStyle').css({ 'height': (($(window).height()) - 350) + 'px' });
});
});
</script>

Using jQuery, it would look something like:
function resetHeight(){
var newHeight = $(window).height() - $('.header').outerHeight() - $('.searchBar').outerHeight() - $('.buttons').outerHeight() - $('.footer').outerHeight();
$('.content').height(newHeight);
}
$(function(){
newHeight();
$(window).resize(function(){
resetHeight();
});
});