Develop Reference

Run Jquery only when an element is in the viewport

I'm trying to perform the Jquery function below when the element becomes visible in the viewport rather than on the page load. What would I need to change to allow that to happen? I'm using an external JS file to perform the Jquery, so keep that in mind.
Here's a piece of the HTML that is associated with the Jquery function -
<div class="skillbar clearfix " data-percent="70%">
<div class="skillbar-title" style="background: #FF704D;">
<span>Illustrator</span></div>
<div class="skillbar-bar" style="background: #FF704D;"></div>
<div class="skill-bar-percent">70%</div>
</div>
jQuery(document).ready(function(){
jQuery('.skillbar').each(function(){
jQuery(this).find('.skillbar-bar').animate({
width:jQuery(this).attr('data-percent')
},4000);
});
});

I once came across such problem and what I used is waypoints small library.
all you need is to include this library and do:
var waypoint = new Waypoint({
element: document.getElementById('waypoint'),
handler: function(direction) {
console.log('Element is in viewport');
}
})

Using CSS3 transitions instead of jQuery animations might be more performant and simpler. a cheap and nasty way of pushing it out of screen to demonstarate the effect.
There's a couple of things you'll need to do - firstly if you only want the animation to trigger when it's in the viewport then you'll need to check if anything is in the viewport on scroll. Then only update the bars width when it comes into view. If you want the effect to repeat every time it comes into viewport you'll need to set .skillbar-bar's width back to 0 if it's out of the viewport (just add an else statement to the viewport checking if)
I've added a 1000px margin-top and 400px margin-bottom in my example to .skillbar as a cheap and nasty way of demonstrating the effect
(function($){
$(document).ready(function(){
var $els = $('.skillbar'); // Note this must be moved to within event handler if dynamically adding elements - I've placed it for performance reasons
var $window = $(window);
$window.on('scroll', function(){
$els.each(function(){ // Iterate over all skillbars
var $this = $(this);
if($window.scrollTop() > $this.offset().top - $window.height()){ // Check if it's in viewport
$this.find('.skillbar-bar').css({'width' : $this.attr('data-percent')}); // Update the view with percentage
}
});
});
});
}(jQuery));
.skillbar{
margin-top: 1000px;
margin-bottom: 400px;
position: relative
}
.skillbar-bar{
transition: width 4s;
position: absolute;
height: 20px;
}
.skill-bar-percent{
position: absolute;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
Scroll down 1000px :)
<div class="skillbar clearfix " data-percent="70%">
<div class="skillbar-title">
<span>Illustrator</span></div>
<div class="skillbar-bar" style="background: #FF704D; width: 20%"></div>
<div class="skill-bar-percent">70%</div>
</div>

This might work for you.
var el = $('.yourElement'),
offset = el.offset(),
scrollTop = $(window).scrollTop();
//Check for scroll position
if ((scrollTop > offset.top)) {
// Code..
}

Bring an element to top of the page even if the page does not scroll

Background:
Let's say you have a simple page which has a logo and a heading only and one paragraph
<img src="http://blog.stackoverflow.com/wp-content/uploads/StackExchangeLogo1.png">
<h1>Foo Bar</h1>
<p>ABC12345</p>
This is how that looks like
That page, obviously would not have vertical overflow / scroll bar for almost even tiny scale mobile devices, let alone computers.
Question
How can you bring that heading to the top left of the screen and move the logo out of focus unless someone scrolls up? Open to using any JavaScript library and any CSS framework
Attempts:
Tried using anchors but they only work if the page already had a scroll bar and anchor was out of focus.
Tried window.scrollTo but that also requires the page to have scroll already
Tried $("html, body").animate({ scrollTop: 90}, 100); but that also doesn't work when the page doesn't have overflow
Notes:
Please note that adding some extra <br/> to induce an overflow is not the way to go, it can be done that way but that's a very ordinary workaround
Why is it needed?
Its for a form for mobile devices, simple requirement is to take the first field of the form to top of the page and hide the logo (one can scroll up if they wish to see it) so it doesn't take attention away. Not using jQueryMobile for this particular task.

If you want the user to be able to scroll up and see the logo, then the logo must be within the top boundary of the body tag, because anything outside of that tag will not be viewable. This means you cannot use negative margins or offsetting like that. The only way to achieve this is to have the page scroll to the desired location that is within the top boundary of the body tag. You can set the time for this event to one millisecond, but there will still be a 'jump' in the page when it is loaded. So, the logic is: first make sure the page is long enough to scroll to the right place, then scroll there.
//Change the jQuery selectors accordingly
//The minimum height of the page must be 100% plus the height of the image
$('body').css('min-height',$(document).height() + $('img').height());
//Then scroll to that location with a one millisecond interval
$('html, body').animate({scrollTop: $('img').height() + 'px'}, 1);
View it here.
Alternatively, you can load the page without the image in the first place. Then your form field will be flush with the top of the document. Then you could create the element at the top and similarly scroll the page again. This is a round-a-bout way of doing the same thing though. And the page will still 'jump,' there is no way around that.

Only CSS and anchor link solution
With a pseudo element :
--- DEMO ---
First :
set : html,body{height:100%;}
Second :
Choose one of your existing tags. This tag mustn't have a relatively positioned parent (except if it is the body tag). Preferably the first element in the markup displayed after the logo. For your example it would be the h1 tag. And give it this CSS :
h1:before {
content:"";
position:absolute;
height:100%;
width:1px;
}
This creates an element as heigh as the viewport area. As it is displayed under the logo, the vertical scroll lenght is the same as the logo height.
Third :
Give the first element after logo an id (for this example I gave id="anchor").
Then you can use a link like this your_page_link#anchor and you will automaticaly scroll to the anchor (logo outside/above the viewport).
This works whatever height the logo is.
link to editable fiddle
Full code :
HTML
<img src="http://blog.stackoverflow.com/wp-content/uploads/StackExchangeLogo1.png">
<h1 id="anchor">Foo Bar</h1>
<p>ABC12345</p> Anchor link
CSS
html, body {
height:100%;
margin:0;
padding:0;
}
h1:before {
content:"";
position:absolute;
width:1px;
left:0;
height:100%;
}

You might need to add js functionality to hide the logo if user scrolls down but I guess following code will fullfill the first requirement.
Please see
<script src="js/jquery.js"></script>
<img id='logo' src="http://blog.stackoverflow.com/wp-content/uploads/StackExchangeLogo1.png" style="display:none">
<h1>Foo Bar</h1>
<p>ABC12345</p>
<script type="text/javascript">
var p = $( "p:first" );
var isScrolled=false;
/* For Firfox*/
$('html').on ('DOMMouseScroll', function (e) {
isScrolled = true;
if(p.scrollTop()==0 && isScrolled==true){
$('#logo').css('display','block');
}
});
/* For Chrome, IE, Opera and Safari: */
$('html').on ('mousewheel', function (e) {
isScrolled = true;
if(p.scrollTop()==0 && isScrolled==true){
$('#logo').css('display','block');
}
});
</script>
I have referred this question to find solution.

You could use touchmove event to detect swipe up or down. This is my example. You can try it on mobile device.
<style>
#logo {
position: absolute;
top: -100%;
-webkit-transition: top 0.5s;
-moz-transition: top 0.5s;
-ms-transition: top 0.5s;
-o-transition: top 0.5s;
transition: top 0.5s;
}
#logo.show {
top: 0;
}
</style>
<script>
var perY;
var y;
$(window).on('touchmove', function(e) {
e.preventDefault();
y = window.event.touches[0].pageY;
if(!perY)
perY = y;
else
{
if(y > perY)
$('#logo').addClass('show');
else
$('#logo').removeClass('show');
perY = null;
}
});
</script>
<img id="logo" src="http://blog.stackoverflow.com/wp-content/uploads/StackExchangeLogo1.png">
<h1>Foo Bar</h1>
<p>ABC12345</p>

This is the same problem i've encountered hiding the addressbar without the page overflowing. The only solution that fitted my needs was the following:
Set the min-height of the body to the viewportheight + your logo.
$('body').css('min-height', $(window).height() + 200);

This is a simple solution of getting the height of the contents to see if we can scroll to the part of the header, if not, we add height to the paragraph.
<img id="img" src="http://blog.stackoverflow.com/wp-content/uploads/StackExchangeLogo1.png" />
<h1 id="h" >Foo Bar</h1>
<p id="par" style="background:yellow;">
hello world
</p>
script:
function hola(){
var imgH = $("#img").outerHeight(true);
var titleH = $("#h").outerHeight(true);
var winH = $(window).height();
var parH = $('#par').outerHeight(true);
var contH = (imgH + titleH + parH);
var wishH = (imgH + winH);
console.log("wished height: " + wishH);
console.log("window height: " + winH);
console.log("content height: " + contH);
if(contH < wishH){
console.log("window is smaller than desired :(");
var newH = wishH - contH;
$("#par").height(parH + newH);
$(window).scrollTop(imgH);
}
}
Here is the working example:
http://jsfiddle.net/Uup62/1/

You may like this solution: http://jsfiddle.net/jy8pT/1/
HTML:
<div class="addScroll"></div>
<h1 class="logo"><img src="https://drupal.org/files/images/OQAAAI1PPrJY0nBALB7mkvju3mkQXqLmzMhxEjeb4gp8aujEUQcLfLyy-Sn4gZdkAas6-k8eYbQlGDE-GCjKfF5gIrUA15jOjFfLRv77VBd5t-WfZURdP9V3PdmT.png" height="100" alt="company logo"/></h1>
<h2>This is a sample page heading.</h2>
<p>This is a sample page text.</p>
JS:
function addScroll()
{
$(".addScroll").css({
"height": ($(window).height()+1) + "px",
"width": "100%"
});
}
$(document).ready(function(){
addScroll();
$(window).resize(function(){
addScroll();
});
$(window).scroll(function(){
if($(window).scrollTop() > 0)
{
$(".logo").animate({
marginTop: "-110px"
}, 500);
}
if($(window).scrollTop() == 0)
{
$(".logo").animate({
marginTop: "0"
}, 500);
}
});
});
CSS:
body
{
padding:0;
margin:0;
}
h1.logo
{
display:block;
margin:0 0 10px 0;
padding:0;
outline:0;
}
.addScroll
{
position:absolute;
display:block;
top:0;
left:0;
z-index:-1;
}

Fixed position element pushed out of relative position element?

So i have the following HTML markup;
<div id ="page_shadow">
<div id="blog_content">
<div id="main_content_container>
Main Content
</div>
<div id="swrapper">
<div id="blog_sidebar">
Sidebar Content
</div>
</div>
</div>
</div>
The following CSS;
#blog_sidebar.fixed {
position: fixed;
top: 0;
}
#swrapper {
position:absolute;
right:0;
}
#blog_sidebar {
width: 330px;
padding:10px;
padding-top:25px;
height:auto;
}
#main_content_container {
width:600px;
float:left;
height:auto;
padding-bottom:15px;
}
#blog_content {
position:relative;
width:960px;
margin-left:auto;
margin-right:auto;
min-height:1300px;
height:auto;
background:#FFFFFF;
z-index:5;
}
#page_shadow {
background:url('../images/background_shadow.png') top center no-repeat;
padding:10px;
margin-top:-60px;
}
The following javascript;
<script>
$(document).ready(function(){
var top = $('#blog_sidebar').offset().top - parseFloat($('#blog_sidebar').css('marginTop').replace(/auto/, 0));
var bottom = $('#blog_content').position().top+$('#blog_content').outerHeight(true) - $('#blog_sidebar').height() - 35;
$(window).scroll(function (event) {
// what the y position of the scroll is
var y = $(this).scrollTop();
// whether that's below the form
if (y >= top) { //&& y <= bottom
// if so, ad the fixed class
$('#blog_sidebar').addClass('fixed');
} else {
// otherwise remove it
$('#blog_sidebar').removeClass('fixed');
}
});
});
</script>
Ok so basically there are two scenarios which occur. IF the page is loaded with the browser viewport above the y position before #blog_sidebar's position is changed to fixed then the element stays within the blog_content container.
HOWEVER, if the page is loaded with if (y >= top) = True resulting in $('#blog_sidebar').addClass('fixed'); the element is then pushed outside the blog_content container.
Again this only occurs if the viewport is = or below the trigger when the page is loaded.
For example if i were to go half way down the page and then click for the page to refresh, the browser loads the page and the element and then jumps to the position it was previously. The fixed position element shown up in the correct position for a split second and then jumps outside #blog_content aligning with the left of the element.
Ive got a little example to show the basics of the layout etc, but i dont think i can show exactly whats happening within jsfiddle. http://jsfiddle.net/ce3V3/
TLDR
Since this is quite confusing. Short version is i am changing a static positioned element with a fixed position element within the DOM, which is resulting in the fixed positioned element being out of place if the window is refreshed and jumps past a certain point. I dont want the fixed position element to jump out of place if a user relaods the page and the window jumps halfway down the page.

Slide gallery with image tooltips, images breaking out of unlimited width block

I'm trying to develop a slide gallery with image tooltips according to this design:
What I need to develop is a slider controlled by two buttons, each time a button is pressed the slider's content must move a width of the slider or the width of the content left on that side, whichever is smaller. Upon mouse entering an image inside the slider the full-size version must be displayed as a tooltip.
Here's a fiddle of my solution so far, the problem I'm having is that images that don't fully fit into view plus the hidden area to the left get moved to a new line. You can see the problem by clicking the
"Show content size" button, the width of the content element will be equal to the width of the container element + content element's margin-left.
Bonus points if you can suggest an algorithm for moving the content to the right, I've got left figured out to a T (or so I think, anyway), but right is going to take a little more work (it doesn't check whether the end of the content has been reached). Update: It seems I can't implement proper movement to the right until the other issue is resolved, here's the algorithm I came up with, I can't measure "left to display" if I can't measure the actual width of the content element.

I created something you might like:
gallery demo
The gallery does not scroll the full gallery width by default (you can change that) cause some initially cut-off images at the right side, after a 'full' slide would result cut-off again, just on the other side of our gallery. You have for that cause the beKind variable. Adjust it as you like.
It hides the buttons if there's not enough content to make the gallery usable.
The gallery calculates the remaining space to scroll.
Once the slider end reached - the left/right buttons make the gallery jump to the beginning/end, so that are always usable. (Seems kinda weird to have a button... but that does nothing right? ;) )
The Tooltip has a hover-intent built in, to not piss off our users if they unintentionally hovered our gallery: (the tooltip fades in if the hover is registered for more that 120ms. Fair timing. I like it.)
As pointed out in your comment now the tooltip will not go off the screen.
jQ:
// Slide Kind Gallery - by roXon // non plugin v. // CC 2012.
$(window).load(function(){
var galW = $('#gallery').outerWidth(true),
beKind = 120, // px substracted to the full animation to allow some images to be fully visible - if initially partly visible.
sumW = 0;
$('#slider img').each(function(){
sumW += $(this).outerWidth(true);
});
$('#slider').width(sumW);
if(sumW <= galW){ $('.gal_btn').remove(); }
function anim(dir){
var sliderPos = Math.abs($('#slider').position().left),
rem = dir ==='-=' ? rem = sumW-(sliderPos+galW) : rem = sliderPos,
movePx = rem<=galW ? movePx = rem : movePx = galW-beKind;
if( movePx <= 10){
movePx = dir==='-=' ? movePx=rem : movePx = galW-sumW;
dir = '';
}
$('#slider').stop(1).animate({left: dir+''+movePx },1000);
}
$('.gal_btn').on('click', function(){
var doit = $(this).hasClass('gal_left') ? anim('+=') : anim('-=');
});
});
And the tooltip script:
// Addon // Tooltip script
var $tt = $('#tooltip');
var ttW2 = $tt.outerWidth(true)/2;
var winW = 0;
function getWW(){ winW = $(window).width(); }
getWW();
$(window).on('resize', getWW);
$('#slider img').on('mousemove',function(e){
var m = {x: e.pageX, y: e.pageY};
if( m.x <= ttW2 ){
m.x = ttW2;
}else if( m.x >= (winW-ttW2) ){
m.x = winW-ttW2;
}
$tt.css({left: m.x-ttW2, top: m.y+10});
}).hover(function(){
$clon = $(this).clone();
var t = setTimeout(function() {
$tt.empty().append( $clon ).stop().fadeTo(300,1);
},120);
$(this).data('timeout', t);
},function(){
$tt.stop().fadeTo(300,0,function(){
$(this).hide();
});
clearTimeout($(this).data('timeout'));
});
HTML
(Place the #tooltip div after the body tag)
<div id="tooltip"></div>
<div id="gallery_container">
<div id="gallery">
<div id="slider">
<img src="" alt="" />
<img src="" alt="" />
</div>
</div>
<div class="gal_left gal_btn">◀</div>
<div class="gal_right gal_btn">▶</div>
</div>
CSS:
/*GALLERY*/
#gallery_container{
position:relative;
margin:0 auto;
width:600px;
padding:0 30px; /*for the buttons */
background:#eee;
border-radius:5px;
box-shadow: 0 2px 3px #888;
}
#gallery{
position:relative;
height:100px;
width:600px;
overflow:hidden;
}
#slider{
position:absolute;
left:0px;
height:100px;
}
#slider img{
height:100.999%; /* fixes some MOZ image resize inconsistencies */
float:left;
cursor:pointer;
border-right:3px solid transparent; /* instead of margin that could leat to some wrong widths calculations. */
}
.gal_btn{
position:absolute;
top:0px;
width:30px; /*the container padding */
height:40px;
padding:30px 0;
text-align:center;
font-size:30px;
cursor:pointer;
}
.gal_left{left:0px;}
.gal_right{right:0px;}
/* end GALLERY */
/* TOOLTIP ADDON */
#tooltip{
position:absolute;
z-index:100;
width:300px;
padding:10px;
background:#fff;
background: rgba(255,255,255,0.3);
box-shadow:0px 3px 6px -2px #111;
display:none;
}
#tooltip *{
width:100%;
vertical-align:middle;
}
/* end TOOLTIP ADDON */
Hope you'll like it, and you learned some useful UI design tricks.
By the way, if you want to populate your ALT attributes (Search engines like it!) you can also grab that text and make it appear inside the tooltip like here!:
demo with text inside the tooltip
Happy coding.

I don't know if I understand correctly your problem. If you set a width wide enough to .scroll-content div, images wouldn't go to the "next line". So a solution would be to set a width with css. If not, you could use jquery to determine the total width of all the images and give it to the .scroll-content div. Calculate total width of Children with jQuery

CSS: dynamic width div

I'm coding a slider and I have problems with the stylying of the container.
I have 3 div:
A div that sets the width and height of the slider
A container div with all the content divs (and the scroll for the slider)
Many divthat show different contents each
What I want to do is apply a negative margin on the second div to slide the content.
LIVE example: http://jsbin.com/efuyix/7/edit
JS:
function animate(element) {
var start = new Date();
var id = setInterval(function() {
var timePassed = new Date() - start;
var progress = timePassed / 600;
if (progress > 1) progress = 1;
element.style.marginLeft = -50 * Math.pow(progress, 5)+"px";
if (progress == 1) {
clearInterval(id);
}
}, 10);
}
CSS
.example_path {
overflow: hidden;
width: 50px;
height: 50px;
}
.example_block {
min-width: 100px;
height: 50px;
float:left;
}
.example_in_block {
width: 50px;
height: 50px;
float:left;
}
HTML
<div class="example_path">
<div class="example_block" onclick="animate(this)">
<div class="example_in_block" style="background-color:blue;"></div>
<div class="example_in_block" style="background-color:pink;"></div>
<div style="clear:both;"></div>
</div>
</div>
The problem:
The width of .example_block has to be exactly the same or more than (amount of content divs .example_block * 50 [width size of content div] ) to work.
For example, if I set the width size of the .example_block to 90, the pink div will be below the blue div and not beside it.
I want the container div to be dynamic so I don't have to set the specific width size.
How can I do this?

Simply remove the float:left in the .example_block.
See http://jsbin.com/efuyix/9/edit

Not with negative margins. You can probably set padding on one of the outer DIVs.
Also, min-width isn't going to be backwards compatible with older versions of IE.
Check this example: http://jsfiddle.net/5xBYN/6/
If the initial positioning is good, you can then use negative values on your container DIV (the third DIV) for top, left, right or bottom to achieve sliding.
Update:
Maybe this is closer to what you want. http://jsfiddle.net/5xBYN/7/
I'm still not sure what you are trying to do. Maybe edit the fiddle I posted and update your question with what I'm getting wrong if there is anything.