Develop Reference

Dynamically calculate top property with javascript

I am trying to write a script, so elements on a page scroll slower/faster than their parent div. I have wrote this:
$('#two').css({'top' : 600-($(this).scrollTop() / 1.2)+"px"});
My element is already 600px from the top and if I start scrolling the page from top-everything is fine, since it has these 600px to calculate from, but if I refresh the page right on the element, it jumps top, and console logs that top is calculated from 0, but not from 600px, where it is placed.
I tried to rewrite using offsetHeight and other methods(e.g.offset().top), but nothing seems to work.
Could you, please, give me a hint on how to make it recalculate dynamically, so when refreshing the page from the middle it won't jump up?

Use position fixed property Even when you scroll the element's position remains fixed.
<style>
#two {
position: fixed;
top: 600px;
}
</style>

Can't get fixed div to stop above the footer, what am I missing?

I have a side bar div that is fixed until a certain scroll/page height and then it becomes position:absolute.
My problem is that, when it loads in, it's at the right position and height, until I scroll and then it moves (partly due to the jQuery function). When it moves however, it makes it so it doesn't stop at the footer, but instead continues past it.
I am building this on a COS so I can't exactly recreate the problem in JSFiddle, but I can link you to the page.
CSS
/*fixed/absolute div*/
.widget-type-post_listing{
right:0;
width:50px;
position:absolute;
display;block;
background:yellow;
height:50px;
}
jQuery
$(function(){
var container = $('.widget-type-post_listing');
var minTop = $('.header-container-wrapper').outerHeight();
var maxTop = $('.footer-container-wrapper').offset().top - container.outerHeight();
$(document).scroll(function() {
container.css('top', Math.min( Math.max(minTop, $(document).scrollTop()), maxTop ));
});
});
Here is the JS Fiddle showing a working example: JSFiddle. You can see that the yellow box (fixed/abso.div) will stick on page until scrolling to footer.
As I said above, to see the exact problem, visit the working page: Working Page
Thanks for the help everyone!

You can add a div in between footer and header surrounding the yellow div 100% width position relative and then fix the max-height of that div and set it's display to inline-flex or inline-block. I think that should so the job.
Cover-div{
width: 100%;
display: inline-flex;
position: relative;
}

Making a sticky header stick to the top

I have managed to make a dropdown for a website I am designing and I'm a bit stuck on the sticky header part..
My header has the sticky effect however when i scroll down the header does not stick to the top of the page. It always maintains a margin of 80px from the top as i mentioned in the CSS.
How can i make the header stick to the TOP when i scroll and when i scroll back to the top of the page it should retain its original position. Hope i have made myself clear.
Just pasting my CSS as the HTML is too lengthy in the fiddle.
#nav, #nav ul {
list-style: none outside none;
margin: 0;
padding: 0;
z-index:9998;
position:relative;
}
Check this fiddle for a DEMO I have created.
EDIT: Just to be clear. I want the top:80px to be there initially. I only want the header to stick to the top while scrolling. EXAMPLE

Here you go.
WORKING DEMO
Changes in CSS:
#nav {
position:fixed;
top:-40px;
}

You have some conflicting styles you need to get rid of:
http://jsfiddle.net/5GqYh/4/
Firstly, you had top inline your header, so I set it to 0.
I also adjust the top margin on your menu, that was also pushing it down.

Try these:
Remove this from ur css to make the header stick to the top.
#nav {
..
margin:40px auto;
..
}
2.css style for header - position:relative will do instead of position:fixed.
3.Put the content div inside another div and create a scrollbar only for that div. In that way, your header will always stick to the top.

Create a .sticky class on your CSS that makes the element's position fixed, then you can easily detect if the user scrolled enough to make it stick to the top, at which point you add the .sticky class to the element. Of course when the user scrolls all the way back you should remove the class. Example:
function stick() {
var stickyNavTop = $('.nav').offset().top;
var scrollTop = $(window).scrollTop();
if(stickyNavTop > scrollTop) {
$('.nav').addClass('sticky');
} else {
$('.nav').removeClass('sticky');
}
}
$(window).scroll(function() {
stick();
});

Interactive HTML webpage

EDIT: Thanks for a lot of great examples on how to solve these. I cant decide between who to accept yet, but I will go though all examples and see which I like the most. Great feedback guys! =D
I normally do these kind of things in flash, but this time it has to be compatible with mac, iPads and all those units too.
So, what do I need help with?
I've got a picture, with some "hotspots" on. I want to be able to click any of those hotspots to show some information.
This should be fairly basic and easy to achieve, but since I've never done this in html before I have to ask you guys =)
So, what would be the best way to do this? It have to be compatible with any browser and device, and it doesnt need to be very advanced. If it's possible to add effects to the box (sliding out, fading in, or anything like that) then thats a nice bonus, but not something I need.
Any help would be great!
BREAKDOWN:
I have a background image with some "hotspots" (numbers 1 and 2 in my example). The users should be able to either hover the mouse over any of these or click it to get more information, as seen in picture #2
This is that happens when you hover/click any of these hotspots.
Text and image is displayed inside a nice little info box.
If the user clicks "more information" it will open up even further to display more information if available. Like in this img:

I don't think the Javascript approach is really necessary here. I created a little CSS-only mock-up for you on JSBin.
Basically the point is that you enclose the image in a relatively positioned div, then absolute position the hotspots inside the same div. Inside the hotspots divs you will have the more info elements, showing only on :hover of their parents.
This makes it simple, and far more accessible.
Update: cropping the image equally from both sides
If you want to keep the image centered and still not use any javascript, you could set the required image as a background-image of the container, and setting its background-position parameters to center center.
You would have to make sure that the width of this div is set to the width of your image, and the max-width to 100%, so that when the window gets resized below the image width it stays at the center.
Now, a problem that I encountered here is how to make the hotspots stay center relatively to the image. I solved it this way:
I created a wrapper div for the hotspots with these characteristics:
margin: 0 auto;
position: relative;
width: 0px;
This basically makes sure that the wrapper div finds the center of our image. Then, you would position the hotspots relatively to the top-center position of the image, instead of the top-left as a starting point.
Then you have what you are looking for.
Working demo

Here's another approach, and in my opinion far superior to using a map or excessive JS. Place <div> elements on top of the element with the background-image and have HTML and CSS do the heavy lifting for you.
See it on JSFiddle
HTML
The HTML should seem pretty each enough to understand, we create <div>s with the class hotspot and rely on certain things being present. Namely .text (to show digit), .hover-popup (to show on hover) and .click-popup (which is inside .hover-popup and is shown when clicked).
<div id="hotspot1" class="hotspot">
<div class="text">1</div>
<div class="hover-popup">
I was hovered!
<div class="click-popup">
I was clicked on!
</div>
</div>
</div>
<div id="hotspot2" class="hotspot">
<div class="text">2</div>
<div class="hover-popup">
I was hovered!
<div class="click-popup">
I was clicked on!
</div>
</div>
</div>
CSS
This is where most of the magic happens, see the comments for further explanation.
/* These two position each hotspot */
#hotspot1 {
left:15%; /* we could use px or position right or bottom also */
top:20%;
}
#hotspot2 {
left:35%;
top:25%;
}
/* General styles on the hotspot */
.hotspot {
border-radius:50%;
width:40px;
height:40px;
line-height:40px;
text-align:center;
background-color:#CCC;
position:absolute;
}
.hotspot .text {
width:40px;
height:40px;
}
/* Show the pointer on hover to signify a click event */
.hotspot .text:hover {
cursor:pointer;
}
/* hide them by default and bring them to the front */
.hover-popup,
.click-popup {
display:none;
z-index:1;
}
/* show when clicked */
.hotspot.clicked .click-popup {
display:block;
}
/* show and position when clicked */
.hotspot:hover .hover-popup {
display:block;
position:absolute;
left:100%;
top:0;
width:300px;
background-color:#BBB;
border:1px solid #000;
}
JavaScript (with jQuery)
Unfortunately you're going to have to use some JavaScript for the clicking part as CSS doesn't have a 'clicked' state (outside of hacks with checkboxes). I'm using jQuery because it's dead easy to do what I want.
$(document).ready(function () {
$('.hotspot').click(function () {
$(this).toggleClass('clicked');
});
});
Creating the arrow
Over at css-tricks you can find a tutorial for attaching an arrow to a element using the :before and/or :after pseudo-elements. You can even 'simulate' a border around them by placing the :after element on top of the :before. But yea, lots of resources on how to do this.

You should be able to use the onclick or OnMouseOver event in the map area (define the href as "").
An example using OnMouseOver is here: http://www.omegagrafix.com/mouseover/mousimap.html

Give a class for that image in html (Ex: imgclass). And in javascript(using jquery), build that hover box in html format and bind it to 'mouseover' event of that image.
For example:
function bindhtmltoimage() {
myimg = $('body').find('.imgclass');
divSlot.each(function (index) {
$(this).bind('mouseover', function () {
try {
//position the hover box on image. you can customize the y and x axis to place it left or right.
var x = $(this).offset().left;
var y = $(this).offset().top;
var position = $(window).height() - ($("#divHover").height() + y);
var widthposition = $(window).width() - ($("#divHover").width() + x);
if (position < 0 || widthposition < 0) {
if (position < 0) {
$("#divHover").css({
position: 'absolute',
left: x + 20,
top: y - $("#divHover").height() - 20
});
}
if (widthposition < 0) {
$("#divHover").css({
position: 'absolute',
left: x - $("#divHover").width(),
top: y + 20
});
}
}
//build your html string for that hover box and apply to it.
$('#divHover').html("your Html content for that box goes here");
$('#divHover').show();
//if you want the box dynamically generated. create the html content and append to the dom.
}
catch (e) {
alert(e)
}
});
});
}
it will work fine in desktop and mobile. if you face any problem in touch devices, bind the function to click event instead of 'mouseover'.
Also, for map approach, i strongly recommend SVG instead of images.

Dynamic Background Scrolling

Here's a link to what I'll be referring to.
I'm having some trouble getting the background image to work the way I'd like it to.
I want the background to auto resize based on the width of the window, which it is already doing correctly. If you make your window smaller you'll see the background shrink with it.
Here's the issue. If you make your window wide (short) then the background will resize and go too high so you can't see the top of the background anymore (since the background is bottom positioned).
I want the background to be top position when you are at the top of the page, and as you scroll down it will slowly move to be bottom positioned. Sort of like the effect of an Android phone's background when you move left and right. Of course, keep in mind that I still want the background to auto-resize when you make the window smaller.
html {
background-color: #70d4e3;
height: 100%;
}
body {
height: 100%;
}
.background {
margin-top: 45px;
width: 100%;
position: fixed;
bottom: 0;
left: 0;
z-index: -9999;
}
.banner {
margin: 0px auto;
width: 991px;
margin-bottom: -9px;
}
.content {
background: url("http://i.imgur.com/daRJl.png") no-repeat scroll center center transparent;
height: 889px;
margin: 0 auto;
width: 869px;
}
.innerContent {
padding: 30px;
}
<img src="http://i.imgur.com/6d5Cm.jpg" alt="" class="background" />
<div class="banner">
<img src="http://i.imgur.com/JptsZ.jpg" alt="" />
</div>
<div class="content">
<div class="innerContent">
testing
</div>
</div>
Maybe some javascript or jquery would be needed to achieve this.

Well, this was fun, thanks!
I hope you don't mind me taking the liberty to use percentages to make my life a little bit easier and possibly the script slightly more robust since I can reliably use floats with percentages.
What I did is make the layout, html and css comply with the rules you need for the bg to be animated properly, they stayed largely the same from what you had.
Then it was just a question of figuring out the calculations needed with the right properties to figure out the percentage you were from the top, the *20 is actually the amount of space 'left' to fill by the background image in percentages (as the background height is 80%).
They I moved the calculations to a function so I could call that on scroll and on window resize, making sure it's initiated on any event that modifies the window somehow...
Didn't do extensive testing but it worked in Chrome and I'm tired :p
I believe this is what you are looking for:
http://jsfiddle.net/sg3s/RSqrw/15/ See edit 2
If you wanted this the other way arround just make the page background start at the top and modify that:
http://jsfiddle.net/sg3s/RSqrw/14/ See edit 2
Edit:
As a bonus, and since I had never actually written jquery script as a 'plugin', I decided to convert this into one. What I came up with should be easy to implement and use!
http://jsfiddle.net/sg3s/RSqrw/52/ See Edit 3
Functionality successfully tested in Chrome, Firefox 3.6, IE9 + compatibility mode
Edit 2:
Reading the question again checking if I did it right I noticed I didn't quite do what you want, so I updated the link in the first edit which gives you a plugin in which you can have several options for the scrolling background. It retains my 'old' interpetation while also doing what you want... Read comments in code for some extra descriptions.
Edit 3:
As I went to work today I was bothered with the fact that my plugin 'try' was a little bloated. And as you mentioned in the comment it didn't quite fit the requirements.
So I rewrote it to only do what you want and not much more, tested in Chrome Firefox, IE9 +compat etc etc.. This script is a lot cleaner.
http://jsfiddle.net/sg3s/vZxHW/
You can chose to make the background stick to the top or bottom if the height fits in the window. Nothing else, but that is already more than enough to do some pretty cool stuff :p

An exact solution: Fiddle: http://jsfiddle.net/srGHE/2/show/
View source
Thanks for the challenge. See below for the solution, which is complying with all requirements, including recommended yet optional (with steps on how to remove these) features. I only show the changed parts of your page, with an explanation after each section (CSS, HTML and JavaScript):
CSS (changes):
html,body{
margin: 0;
height: 100%;
padding: 0;
}
body{
background-color: #70d4e3;
}
#background { /*Previously: .background*/
/*Removed: margin-top: 45px;
No other changes*/
}
#banner /*Previously: .banner; no other changes */
#content /*Previously: .content; no other changes */
#innerContent /*Previously: .innerContent; no other changes */
Explanation of CSS revisions:
margin-top:45px at the background is unnecessary, since you're absolutely positioning the element.
All of the elements which are unlikely to appear more than once should be selected via the id (#) selector. This selector is more specific than the class selector.
HTML (changes):
All of the class attributes have been replaced by id. No other changes have been made. Don't forget to include the JQuery framework, because I've implemented your wishes using JQuery.
JavaScript (new):
Note: I have added a feature which you didn't request, but seems logical. The code will automatically reserve sufficient margin at the left side of the window in order to always display the background. Remove anything between the marked comments if you don't want this feature.
$(document).ready(function(){
//"Static" variables
var background = $("#background");
var marginTop = parseFloat(background.css("margin-top")) || 0;
var bannerWidth = $("#banner").width(); /*Part of auto left-margin */
var extraContWidth = (bannerWidth - $("#content").width())/2; /*Same as above*/
function fixBG(){
var bodyWidth = $("body").width();
var body_bg_width_ratio = bodyWidth/1920;
var bgHeight = body_bg_width_ratio * 926; //Calcs the visible height of BG
var height = $(document).height();
var docHeight = $(window).height();
var difHeight = bgHeight - docHeight;
var scrollDif = $(document).scrollTop() / (height - docHeight) || 0;
/*Start of automatic left-margin*/
var arrowWidth = body_bg_width_ratio * 115; //Arrow width
if(bodyWidth - bannerWidth > arrowWidth*2){
$("body > div").css("margin-left", "auto");
} else {
$("body > #banner").css("margin-left", arrowWidth+"px");
$("body > #content").css("margin-left", (arrowWidth+extraContWidth)+"px");
}
/*End of automatic left-margin*/
if(difHeight > 0){
background.css({top:(-scrollDif*difHeight-marginTop)+"px", bottom:""});
} else {
background.css({top:"", bottom:"0"});
}
}
$(window).resize(fixBG);
$(window).scroll(fixBG);
fixBG();
});
Explanation of the JavaScript code
The size of the background is determined by calculating the ratio of the background and document width. The width property is used, because it's the most reliable method for the calculation.
Then, the height of the viewport, document body and background is calculated. If applicable, the scrolling offset is also calculated, to prepare the movement of the background, if necessary.
Optionally, the code determines whether it's necessary to adjust the left margin (to keep the background visible at a narrow window).
Finally, if the background arrow has a greater height than the document's body, the background is moved accordingly, taking the scrolling position into account. The arrow starts at the top of the document, and will move up as the user scrolls (so that the bottom side of the arrow will be the bottom of the page when the user has fully scrolled down). If it's unnecessary to move the background, because it already suits well, the background will be positioned at the bottom of the page.
When the page has finished loading, this functionality is added to the Resize and scroll events, so that the background is always at the right location.
If you've got any other questions, feel free to ask them.

well, I'm not sure if I understand you and why do you want to do that, but you can try adding 2 backgrounds (see http://www.css3.info/preview/multiple-backgrounds/ ), one with the top bg and another with the bottom bg but I think that if the page is not too long it will cause issues, so the other answer with pure CSS is as follows: first add 3 horizontal divs with 100% width. Top div will have your top bg and its height, middle div will be transparent and auto height and bottom div will have your bottom bg and its height. All divs will have a 0 z-index. Then create a higher z-index div to act as a container and you'll be set. If I understand your question right, that's the close I can think of to achieve that. This being said, I'm pretty sure you can do this with JQuery with way better results

Using jQuery I was able to give you what I think you're asking for:
$(window).scroll(function() {
var h = Math.max($(document).height(), $(window).height());
var bottom = h - $(".background").height() - $(window).height();
$(".background").css("top", (($(window).scrollTop() / h) * bottom) + "px");
});
EDIT: Forgot to account for the way scrollTop reports position.

Or maybe:
.background {
margin-top: 45px;
max-width: 100%;
position: fixed;
bottom: 0;
left: 0;
z-index: -9999;
max-height: 100%;
}

I reccomend using jQuery Background Parallax
http://www.stevefenton.co.uk/Content/Jquery-Background-Parallax/
The function is as simple as
$("body").backgroundparallax();
Ask if you don't get it to work.

#abney; as i understand your question may that's you want http://jsfiddle.net/sandeep/RSqrw/60/
you need only css for this:
#background {
position: fixed;
width: 100%;
height:100%;
top: 0;
left:0;
z-index: -1;
}

The solution to your issue is a nice little lightweight plugin by Scott Robin. You can get more info, download it, and make your life easier for all of your projects by visiting his project page here.