Develop Reference

How to make my animated skills bar responsive

I have an animated skills bar on my website, which fires when the section scrolls into view. Everything is working well so far.
Except when the viewport changes/window resizes the animated bars won't adjust to it and will be too long or to short.
I tried to solve this problem with
$(window).resize(function(){location.reload();
but on mobile viewport it keeps refreshing the page even though I'm just scrolling.
I already searched the net to see if there is a way to just reload the specific jquery function, but couldn't find anything. Or to be honest I didn't quite understood I guess, and couldn't get it working.
Here is what I found: https://css-tricks.com/forums/topic/reload-jquery-functions-on-ipad-orientation-change/
I read there is a way to make the website reload the whole js file. But since I still have other animations on my page, I don't know if this is the best way to do it.
I'm glad if anyone could help me with this. I'm very new to coding and my js/jquery knowledge is still very limited/non-existent.
here is my script for the bar animation
var $meters = $(".meter > span");
var $section = $('#skills .meter');
var $queue = $({});
function loadDaBars() {
$meters.each(function() {
var $el = $(this);
var origWidth = $el.width();
$el.width(0);
$queue.queue(function(next) {
$el.animate({width: origWidth}, 800, next);
});
});
}
$(document).bind('scroll', function(ev) {
var scrollOffset = $(document).scrollTop();
var containerOffset = $section.offset().top - window.innerHeight;
if (scrollOffset > containerOffset) {
loadDaBars();
$(document).unbind('scroll');
}
});
the width for the skillbar is defined via div class and span in %.
Maybe there is a css solution to this?
edit: this is how my html and css code looks like
.meter {
background-color: hsla(54, 73%, 95%, 1);
vertical-align: bottom;
width: 100%;
position: relative;
}
.meter>span {
display: block;
background-color: rgb(241, 233, 166);
position: relative;
overflow: hidden;
}
<div class="col-lg-6 col-md-6 col-sm-6">
<div class="meter">
<span style="width: 50%"></span>
</div>

You remove the style property of the bar once the animation has finished. This way the css rule will apply again:
$el.animate({width: origWidth}, {duration: 800, complete: function (){$el.removeAttr('style')}}, next);
(Assuming the width defined by the css is responsive)

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;
}

Proportional image scaling

I have a div of known size and a link to some image with random size, which i want to show inside this div. I would like an image to have proportional scaling, to be as big as posible, but no bigger than div (either the image width should equal the div's width or the image height should equal the div's height, but i dont exactly know which case).
How could i do it using only html, css, javascript and jquery?
And it would be great not to read the image size.

You can do this with pure CSS by setting max-width and max-height to 100%. This is a great article to read on the subject: http://unstoppablerobotninja.com/entry/fluid-images. The article also discusses how to deal with older versions of IE.
Here's an example of the CSS in action - http://jsfiddle.net/JamesHill/R7bAA/
HTML
<div id='div1'>
<img class='myImageClass' src='http://www.google.com/intl/en_com/images/srpr/logo3w.png' />
</div>
<br />
<div id='div2'>
<img class='myImageClass' src='http://www.google.com/intl/en_com/images/srpr/logo3w.png' />
</div>
CSS
#div1
{
height:100px;
width:200px;
background-color:Gray;
border: 1px solid Black;
}
#div2
{
height:500px;
width:100px;
background-color:Gray;
border: 1px solid Black;
}
.myImageClass
{
max-height:100%;
max-width:100%;
}

Here's a javascript method that computes the aspect ratio of image and container and sets the corresponding height or width value that will first hit the edge and the image then scales the other dimension proportionally:
// pre-cache image
var img1 = new Image();
img1.src = "http://photos.smugmug.com/photos/344291068_HdnTo-L.jpg";
var img2 = new Image();
img2.src = "http://photos.smugmug.com/photos/344291068_HdnTo-L.jpg";
function placeImage(imgObj, containerID) {
var container = $(containerID);
var imageAspectRatio = imgObj.height / imgObj.width;
var containerAspectRatio = container.height() / container.width();
// figure out which dimension hits first and set that to match
if (imageAspectRatio > containerAspectRatio) {
imgObj.style.height = container.height() + "px";
} else {
imgObj.style.width = container.width() + "px";
}
container.append(imgObj);
}
$("#go").click(function() {
placeImage(img1, "#container1");
placeImage(img2, "#container2");
});
You can see it here in this jsFiddle: http://jsfiddle.net/jfriend00/5K3Zf/

jQuery: Animating width/height, but Stay Centered

I have an element on the page that I've already centered horizontally and vertically (It's a jQuery UI Modal Dialog), and want to resize it using .animate() like this:
<div id="element" style="width: 100px; height: 100px;">
Hi Stack Overflow!
</div>
<script type="text/javascript">
$('#element').animate({ height: "200px" });
</script>
That works fine, except the element only grows downwards. What I'm trying to do is have the element grow vertically in both directions (in this case 50px in each direction) so it stays centered. Is there a way that it can be done?

Live Demo
var growEl = $("#grow"),
curHeight = $("#grow").height(),
curTop = growEl.offset().top,
newHeight = 200,
newMargin = curTop -(newHeight -curHeight)/2;
if(newMargin < 0){
newMargin = 0;
}
$("#grow").animate({height:newHeight+"px", marginTop:newMargin + 'px'});
Formula for figuring out what to make the margin
NewTopMargin = CurrentMargin-(NewHeight-OldHeight)/2
Thanks #bobsoap for reminding me to use offset.top

margin-top: -50px, height: 50px;
That sort of thing (sorry its not code formatted) i'm sure you can insert it correctly.