I have a page with a lot of GIFs.
<img src="gif/1303552574110.1.gif" alt="" >
<img src="gif/1302919192204.gif" alt="" >
<img src="gif/1303642234740.gif" alt="" >
<img src="gif/1303822879528.gif" alt="" >
<img src="gif/1303825584512.gif" alt="" >
What I'm looking for
1 On page load => Animations for all gifs are stopped
2 On mouseover => Animations starts for that one gif
3 On mouseout => Animation stops again for that gif
I suppose this can be done in Jquery but I don't know how.
No, you can't control the animation of the images.
You would need two versions of each image, one that is animated, and one that's not. On hover you can easily change from one image to another.
Example:
$(function(){
$('img').each(function(e){
var src = $(e).attr('src');
$(e).hover(function(){
$(this).attr('src', src.replace('.gif', '_anim.gif'));
}, function(){
$(this).attr('src', src);
});
});
});
Update:
Time goes by, and possibilities change. As kritzikatzi pointed out, having two versions of the image is not the only option, you can apparently use a canvas element to create a copy of the first frame of the animation. Note that this doesn't work in all browsers, IE 8 for example doesn't support the canvas element.
I realise this answer is late, but I found a rather simple, elegant, and effective solution to this problem and felt it necessary to post it here.
However one thing I feel I need to make clear is that this doesn't start gif animation on mouseover, pause it on mouseout, and continue it when you mouseover it again. That, unfortunately, is impossible to do with gifs. (It is possible to do with a string of images displayed one after another to look like a gif, but taking apart every frame of your gifs and copying all those urls into a script would be time consuming)
What my solution does is make an image looks like it starts moving on mouseover. You make the first frame of your gif an image and put that image on the webpage then replace the image with the gif on mouseover and it looks like it starts moving. It resets on mouseout.
Just insert this script in the head section of your HTML:
$(document).ready(function()
{
$("#imgAnimate").hover(
function()
{
$(this).attr("src", "GIF URL HERE");
},
function()
{
$(this).attr("src", "STATIC IMAGE URL HERE");
});
});
And put this code in the img tag of the image you want to animate.
id="imgAnimate"
This will load the gif on mouseover, so it will seem like your image starts moving. (This is better than loading the gif onload because then the transition from static image to gif is choppy because the gif will start on a random frame)
for more than one image just recreate the script create a function:
<script type="text/javascript">
var staticGifSuffix = "-static.gif";
var gifSuffix = ".gif";
$(document).ready(function() {
$(".img-animate").each(function () {
$(this).hover(
function()
{
var originalSrc = $(this).attr("src");
$(this).attr("src", originalSrc.replace(staticGifSuffix, gifSuffix));
},
function()
{
var originalSrc = $(this).attr("src");
$(this).attr("src", originalSrc.replace(gifSuffix, staticGifSuffix));
}
);
});
});
</script>
</head>
<body>
<img class="img-animate" src="example-static.gif" >
<img class="img-animate" src="example-static.gif" >
<img class="img-animate" src="example-static.gif" >
<img class="img-animate" src="example-static.gif" >
<img class="img-animate" src="example-static.gif" >
</body>
That code block is a functioning web page (based on the information you have given me) that will display the static images and on hover, load and display the gif's. All you have to do is insert the url's for the static images.
I think the jQuery plugin freezeframe.js might come in handy for you. freezeframe.js is a jQuery Plugin To Automatically Pause GIFs And Restart Animating On Mouse Hover.
I guess you can easily adapt it to make it work on page load instead.
The best option is probably to have a still image which you replace the gif with when you want to stop it.
<img src="gif/1303552574110.1.gif" alt="" class="anim" >
<img src="gif/1302919192204.gif" alt="" class="anim" >
<img src="gif/1303642234740.gif" alt="" class="anim" >
<img src="gif/1303822879528.gif" alt="" class="anim" >
<img src="gif/1303825584512.gif" alt="" class="anim" >
$(window).load(function() {
$(".anim").src("stillimage.gif");
});
$(".anim").mouseover(function {
$(this).src("animatedimage.gif");
});
$(".anim").mouseout(function {
$(this).src("stillimage.gif");
});
You probably want to have two arrays containing paths to the still and animated gifs which you can assign to each image.
found a working solution here:
https://codepen.io/hoanghals/pen/dZrWLZ
JS here:
var gifElements = document.querySelectorAll('img.gif');
for(var e in gifElements) {
var element = gifElements[e];
if(element.nodeName == 'IMG') {
var supergif = new SuperGif({
gif: element,
progressbar_height: 0,
auto_play: false,
});
var controlElement = document.createElement("div");
controlElement.className = "gifcontrol loading g"+e;
supergif.load((function(controlElement) {
controlElement.className = "gifcontrol paused";
var playing = false;
controlElement.addEventListener("click", function(){
if(playing) {
this.pause();
playing = false;
controlElement.className = "gifcontrol paused";
} else {
this.play();
playing = true;
controlElement.className = "gifcontrol playing";
}
}.bind(this, controlElement));
}.bind(supergif))(controlElement));
var canvas = supergif.get_canvas();
controlElement.style.width = canvas.width+"px";
controlElement.style.height = canvas.height+"px";
controlElement.style.left = canvas.offsetLeft+"px";
var containerElement = canvas.parentNode;
containerElement.appendChild(controlElement);
}
}
Pure JS implementation https://jsfiddle.net/clayrabbit/k2ow48cy/
(based on canvas solution from https://codepen.io/hoanghals/pen/dZrWLZ)
[].forEach.call(document.querySelectorAll('.myimg'), function(elem) {
var img = new Image();
img.onload = function(event) {
elem.previousElementSibling.getContext('2d').drawImage(img, 0, 0);
};
img.src = elem.getAttribute('data-src');
elem.onmouseover = function(event) {
event.target.src = event.target.getAttribute('data-src');
};
elem.onmouseout = function(event) {
event.target.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=";
};
});
.mydiv{
width: 320px;
height: 240px;
position: relative;
}
.mycanvas, .myimg {
width: 100%;
height: 100%;
position: absolute;
}
<div class="mydiv">
<canvas class="mycanvas" width=320 height=240></canvas>
<img class="myimg" data-src="https://media.giphy.com/media/Byana3FscAMGQ/giphy.gif">
</div>
You can solve this by having a long stripe that you show in steps, like a filmstrip. Then you can stop the film on any frame.
Example below (fiddle available at http://jsfiddle.net/HPXq4/9/):
the markup:
<div class="thumbnail-wrapper">
<img src="blah.jpg">
</div>
the css:
.thumbnail-wrapper{
width:190px;
height:100px;
overflow:hidden;
position:absolute;
}
.thumbnail-wrapper img{
position:relative;
top:0;
}
the js:
var gifTimer;
var currentGifId=null;
var step = 100; //height of a thumbnail
$('.thumbnail-wrapper img').hover(
function(){
currentGifId = $(this)
gifTimer = setInterval(playGif,500);
},
function(){
clearInterval(gifTimer);
currentGifId=null;
}
);
var playGif = function(){
var top = parseInt(currentGifId.css('top'))-step;
var max = currentGifId.height();
console.log(top,max)
if(max+top<=0){
console.log('reset')
top=0;
}
currentGifId.css('top',top);
}
obviously, this can be optimized much further, but I simplified this example for readability
A more elegant version of Mark Kramer's would be to do the following:
function animateImg(id, gifSrc){
var $el = $(id),
staticSrc = $el.attr('src');
$el.hover(
function(){
$(this).attr("src", gifSrc);
},
function(){
$(this).attr("src", staticSrc);
});
}
$(document).ready(function(){
animateImg('#id1', 'gif/gif1.gif');
animateImg('#id2', 'gif/gif2.gif');
});
Or even better would be to use data attributes:
$(document).ready(function(){
$('.animated-img').each(function(){
var $el = $(this),
staticSrc = $el.attr('src'),
gifSrc = $el.data('gifSrc');
$el.hover(
function(){
$(this).attr("src", gifSrc);
},
function(){
$(this).attr("src", staticSrc);
});
});
});
And the img el would look something like:
<img class="animated-img" src=".../img.jpg" data-gif-src=".../gif.gif" />
Note: This code is untested but should work fine.
For restarting the animation of a gif image, you can use the code:
$('#img_gif').attr('src','file.gif?' + Math.random());
Related answer, you can specify the number of playbacks on a gif. The below gif has 3 playbacks associated with it (10 second timer, 30 second playback total). After 30 seconds have passed since page load, it stops at "0:01".
Refresh the page to restart all 3 playbacks
You have to modify the gif itself. An easy tool is found here for modifying GIF playbacks https://ezgif.com/loop-count.
To see an example of a single-loop playback gif in action on a landing page, checkout this site using a single playback gif https://git-lfs.github.com/
This answer builds on that of Sourabh, who pointed out an HTML/CSS/JavaScript combo at https://codepen.io/hoanghals/pen/dZrWLZ that did the job. I tried this, and made a complete web page including the CSS and JavaScript, which I tried on my site. As CodePens have a habit of disappearing, I decided to show it here. I'm also showing a simplified stripped-to-essentials version, to demonstrate the minimum that one needs to do.
I must also note one thing. The code at the above link, whose JavaScript Sourabh copies, refers to a JavaScript constructor SuperGif() . I don't think Sourabh explained that, and neither does the CodePen. An easy search showed that it's defined in buzzfeed /
libgif-js , which can be downloaded from https://github.com/buzzfeed/libgif-js#readme . Look for the control that the red arrow below is pointing at, then click on the green "Code" button. (N.B. You won't see the red arrow: that's me showing you where to look.)
A menu will pop up offering various options including to download a zip file. Download it, and extract it into your HTML directory or a subdirectory thereof.
Next, I'm going to show the two pages that I made. The first is derived from the CodePen. The second is stripped to its essentials, and shows the minimum you need in order to use SuperGif.
So here's the complete HTML, CSS, and JavaScript for the first page. In the head of the HTML is a link to libgif.js , which is the file you need from the zip file. Then, the body of the HTML starts with some text about cat pictures, and follows it with a link to an animated cat GIF at https://media.giphy.com/media/Byana3FscAMGQ/giphy.gif .
It then continues with some CSS. The CodePen uses SCSS, which for anyone who doesn't know, has to be preprocessed into CSS. I've done that, so what's in the code below is genuine CSS.
Finally, there's the JavaScript.
<html>
<head>
<script src="libgif-js-master/libgif.js"></script>
</head>
<body>
<div style="width: 600px; margin: auto; text-align: center; font-family: arial">
<p>
And so, the unwritten law of the internet, that any
experiment involving video/images must involve cats in
one way or another, reared its head again. When would
the internet's fascination with cats come to an end?
Never. The answer is "Never".
</p>
<img src='https://media.giphy.com/media/Byana3FscAMGQ/giphy.gif' class='gif' />
</div>
<style>
img.gif {
visibility: hidden;
}
.jsgif {
position: relative;
}
.gifcontrol {
position: absolute;
top: 0px;
left: 0px;
width: 100%;
height: 100%;
cursor: pointer;
transition: background 0.25s ease-in-out;
z-index: 100;
}
.gifcontrol:after {
transition: background 0.25s ease-in-out;
position: absolute;
content: "";
display: block;
left: calc(50% - 25px);
top: calc(50% - 25px);
}
.gifcontrol.loading {
background: rgba(255, 255, 255, 0.75);
}
.gifcontrol.loading:after {
background: #FF9900;
width: 50px;
height: 50px;
border-radius: 50px;
}
.gifcontrol.playing {
/* Only show the 'stop' button on hover */
}
.gifcontrol.playing:after {
opacity: 0;
transition: opacity 0.25s ease-in-out;
border-left: 20px solid #FF9900;
border-right: 20px solid #FF9900;
width: 50px;
height: 50px;
box-sizing: border-box;
}
.gifcontrol.playing:hover:after {
opacity: 1;
}
.gifcontrol.paused {
background: rgba(255, 255, 255, 0.5);
}
.gifcontrol.paused:after {
width: 0;
height: 0;
border-style: solid;
border-width: 25px 0 25px 50px;
border-color: transparent transparent transparent #ff9900;
}
</style>
<script>
var gifElements = document.querySelectorAll('img.gif');
for(var e in gifElements) {
var element = gifElements[e];
if(element.nodeName == 'IMG') {
var supergif = new SuperGif({
gif: element,
progressbar_height: 0,
auto_play: false,
});
var controlElement = document.createElement("div");
controlElement.className = "gifcontrol loading g"+e;
supergif.load((function(controlElement) {
controlElement.className = "gifcontrol paused";
var playing = false;
controlElement.addEventListener("click", function(){
if(playing) {
this.pause();
playing = false;
controlElement.className = "gifcontrol paused";
} else {
this.play();
playing = true;
controlElement.className = "gifcontrol playing";
}
}.bind(this, controlElement));
}.bind(supergif))(controlElement));
var canvas = supergif.get_canvas();
controlElement.style.width = canvas.width+"px";
controlElement.style.height = canvas.height+"px";
controlElement.style.left = canvas.offsetLeft+"px";
var containerElement = canvas.parentNode;
containerElement.appendChild(controlElement);
}
}
</script>
</body>
</html>
When I put the page on my website and displayed it, the top looked like this:
And when I pressed the pink button, the page changed to this, and the GIF started animating. (The cat laps water falling from a tap.)
To end, here's the second, simple, page. Unlike the first, this doesn't have a fancy Play/Pause control that changes shape: it just has two buttons. The only thing the code does that isn't essential is to disable whichever button is not relevant, and to insert some space between the buttons.
<html>
<head>
<script src="libgif-js-master/libgif.js"></script>
</head>
<body>
<button type="button" onclick="play()"
id="play_button"
style="margin-right:9px;"
>
Play
</button>
<button type="button" onclick="pause()"
id="pause_button"
>
Pause
</button>
<img src="https://media.giphy.com/media/Byana3FscAMGQ/giphy.gif"
id="gif"
/>
<script>
var gif_element = document.getElementById( "gif" );
var supergif = new SuperGif( {
gif: gif_element,
progressbar_height: 0,
auto_play: false
} );
supergif.load();
function play()
{
var play_button = document.getElementById( "play_button" );
play_button.disabled = true;
var pause_button = document.getElementById( "pause_button" );
pause_button.disabled = false;
supergif.play();
}
function pause()
{
var play_button = document.getElementById( "play_button" );
play_button.disabled = false;
var pause_button = document.getElementById( "pause_button" );
pause_button.disabled = true;
supergif.pause();
}
pause_button.disabled = true;
</script>
</body>
</html>
This, plus the example.html file in libgif-js, should be enough to get anyone started.
There is only one way from what I am aware.
Have 2 images, first a jpeg with first frame(or whatever you want) of the gif and the actual gif.
Load the page with the jpeg in place and on mouse over replace the jpeg with the gif. You can preload the gifs if you want or if they are of big size show a loading while the gif is loading and then replace the jpeg with it.
If you whant it to bi linear as in have the gif play on mouse over, stop it on mouse out and then resume play from the frame you stopped, then this cannot be done with javascript+gif combo.
Adding a suffix like this:
$('#img_gif').attr('src','file.gif?' + Math.random());
the browser is compelled to download a new image every time the user accesses the page. Moreover the client cache may be quickly filled.
Here follows the alternative solution I tested on Chrome 49 and Firefox 45.
In the css stylesheet set the display property as 'none', like this:
#img_gif{
display:'none';
}
Outside the '$(document).ready' statement insert:
$(window).load(function(){ $('#img_gif').show(); });
Every time the user accesses the page, the animation will be started after the complete load of all the elements. This is the only way I found to sincronize gif and html5 animations.
Please note that:
The gif animation will not restart after refreshing the page (like pressing "F5").
The "$(document).ready" statement doesn't produce the same effect of "$(window).load".
The property "visibility" doesn't produce the same effect of "display".
css filter can stop gif from playing in chrome
just add
filter: blur(0.001px);
to your img tag then gif freezed to load via chrome performance concern :)
I was testing out coding an image slider as a project to learn HTML, CSS and Javascript and it works great. I'd just like to implement a few tweaks on it and was wondering if anyone had any idea on how to do this. Bear in mind, I'm relatively new to this so a few explanatory comments would be greatly appreciated.
Here are the tweaks I'd like to implement: When the user hovers over the image, I'd like the slider to stop on that particular image so the user can look at it for as long as they wish. The slider resumes once the mouse is moved (a topic not explored on any questions here as far as I can find). Another thing I'd like to be able to do is create a more aesthetic fade transition between the images. There are tutorials out there for this but they don't give a lot of context for a beginner like me to implement it. Here's the jsfiddle, as requested, http://jsfiddle.net/7m9j0ttL/
<html>
<head>
<style type="text/css">
.container {
max-width: 400px;
background-color: black;
margin: 0 auto;
text-align: center;
position: relative;
}
.container div {
background-color: white;
width: 100%;
display: inline-block;
display: none;
}
.container img {
width: 100%;
height: auto;
}
</style>
</head>
<body>
<section class="demo">
<div class="container">
<div style="display: inline-block;">
<img src="Chrysanthemum.jpg" width="1024" height="768" />
</div>
<div>
<img src="Desert.jpg" width="1024" height="768" />
</div>
<div>
<img src="Hydrangeas.jpg" width="1024" height="768" />
</div>
</div>
</section>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script>
$(document).ready(function() {
var currentIndex = 0,
items = $('.container div'),
itemAmt = items.length;
function cycleItems() {
var item = $('.container div').eq(currentIndex);
items.hide();
item.css('display', 'inline-block');
}
var autoSlide = setInterval(function() {
currentIndex += 1;
if (currentIndex > itemAmt - 1) {
currentIndex = 0;
}
cycleItems();
}, 9000);
});
</script>
</body>
</html>
Updated your fiddle
$('.demo').hover(function(){
clearInterval(autoSlide);
},function(){
autoSlide = setInterval(function() {
currentIndex += 1;
if (currentIndex > itemAmt - 1) {
currentIndex = 0;
}
cycleItems();
}, 1000);
});
Added a hover handler to the .demo element. Cleared interval on hover, this would help stop the slide show. And re-set interval on mouseout to start the slideshow per the set interval.
I don't know whether such kind of answer is acceptable for you, but someday, a few years ago, I created my own slider when I was studying jquery.
Looking at your code, I have questions:
1. Why don't you use rather standard functions like fadeIn() and fadeOut() for transitions?
2. Why don't you make a function that will be able to run simultaneously with any number of tags on the page?
A few years ago I had these questions in my head and I came here, to stackoverflow to learn how to do that from other people. And I learnt (not only here, though).
And I created a function that could be loaded anywhere in the code - I studied how to do that. Then I added fade and slide effects there and also any other things...
This function is not really good, but PROBABLY it will sched some light for you in slider creation process. Sorry for many words, check what I have here:
https://jsfiddle.net/7m9j0ttL/3/
I hope my effort is useful for you. If you are going to go further with this and have questions - I would be glad to answer them.
Last comments:
So my main aim was to create function that could be ran like this:
$('.container').okwbSlider({ActAsDefined: 'fadeItOut', SlidingTag: 'div', timeOut: 3000});
so, here you can see that almost ANY tag, containing ANY other tags (with images, text etc in it) can be slided.
in order to make everything slided after some time, I thought that I have to break function in 2 parts: one accepts parameters and the second is called using javascript's setInterval.
So, here's the first one:
(function($){
$.fn.okwbSlider = function(params) {
//outer variables
var tgDfnr = this;
var somevar = this;
var MouseStatevar = 0;
var globalTimervar = (params.globalTimervar != undefined) ? params.globalTimervar : 4000;
var ActAsDefined = (params.ActAsDefined != undefined) ? params.ActAsDefined : "fadeItOut";
var SlidingTag = (params.SlidingTag != undefined) ? params.SlidingTag : 'img';
var numberOfChildren = tgDfnr.children(SlidingTag).length;
// alert('tgDfnr='+tgDfnr+' globalTimervar='+globalTimervar+' ActAsDefined='+ActAsDefined+' numberOfChildren='+numberOfChildren);
//alert("<"+tgDfnr.prop("tagName")+" id="+tgDfnr.attr('id')+">");
if (numberOfChildren > 1){
setInterval(function(){
okwbSlideIt(tgDfnr, ActAsDefined, numberOfChildren, MouseStatevar, SlidingTag);
}, globalTimervar);
}
if(numberOfChildren == 1){
tgDfnr.children(SlidingTag).fadeIn(500, function(){
$(this).addClass('active');
});
}
}
})(jQuery);
it contains everything that needed to run the function in jquery-like way (i.e. placing it after $('.yourANYClassNameOrId'))
and the second one (it's place higher in the text - re-accepts the entered parameters and works with them. It's written not in the really best way (I would write it much better now), but at least I think if you look at it, you can understand something useful.
So, let me know if you have questions and/or I can help you further.
I'm pretty much a newbie on the HTML/CSS realm and have been facing a jquery challenge ever since I started building my first website. I want to create an jquery-powered image gallery, using thumbnails. The tutorial I followed for that matter was Ivan Lazarevic's (http://workshop.rs/2010/07/create-image-gallery-in-4-lines-of-jquery/). I also made use of Stackoverflow's forum through this thread: http://goo.gl/ILzsx.
The code he provides replaces the large image on display with the larger version of the thumbnail that's been clicked. This seems to work pretty smoothly but just for pictures that have the same orientation. The following code appears on two different files, thus establishing a difference between the horizontal and vertical images:
<div id="mainImage">
<img id="largeImage" src="Images/Projects/UOW/UOWII_large.jpg"/>
</div>
AND:
<div id="mainImageVERTICAL">
<img id="largeImageVERTICAL" src="Images/Projects/UOW/UOWI_large.jpg" />
</div>
I have created different CSS rules for both the largeImage and largeImageVERTICAL parameters, depending on whether the image has a portrait or landscape orientation.
#largeImage {
position: fixed;
height: 83%;
width:auto;
top: 15%;
left: 5%;
}
AND:
#largeImageVERTICAL {
position: fixed;
height: 83%;
width:auto;
top: 15%;
left: 36.36%;
}
These two rules just place the images at different points of the screen. However, what I would like to know is how to modify my code so that I can create a page with both portrait and landscape-oriented images applying the CSS rule that belongs to each. Up to now, what I have is what I got from Lazarevic's approach, which is:
$('#thumbs img').click(function(){
$('#largeImage').attr('src',$(this).attr('src').replace('thumb','large'));
});
This code just replaces the thumbnails with the bigger pictures. As stated, I want to be able to apply the right rule to the right image and I'm assuming this has to be be made through some JS coding, which I know pretty much nothing about.
I would appreciate some help so that I can keep on with this project. Any ideas how to make this work? Maybe a JS function that tells the machine to use one or another CSS rule depending on which image is clicked upon? I'm really stuck here...
Thanks in advance!
There are a couple of ways you could do this.
Use a HTML5 data-* attribute to specify which of the <img> elements should be updated. So:
<div id="thumbs">
<img src="img.jpg" data-large="largeImage"/>
<img src="anotherimg.jpg" data-large="largeImageVERTICAL"/>
</div>
Then:
$('#thumbs img').click(function(e) {
var imageId = $(this).attr('data-large'),
newSrc = this.src.replace('thumb', 'large');
$('#' + imageId).attr('src', newSrc);
});
Or, use the dimensions of the thumbnail to determine whether it's portrait or landscape:
$('#thumbs img').click(function(e) {
var $this = $(this),
height = $this.height(),
width = $this.width(),
newSrc = this.src.replace('thumb', 'large');
var imageId = (height > width) ? 'largeImageVERTICAL' : 'largeImage';
$('#' + imageId).attr('src', newSrc);
});
In either case, you'll probably need to hide the other, unused <img> element so that you don't have the previously selected image for the other orientation displayed.
One way to achieve this would be:
var alternateImageId = (imageId === 'largeImage') ? 'largeImageVERTICAL' : 'largeImage';
$('#' + alternateImageId).hide();
Add the above two lines to the click event handler above, and call .show() after calling .attr('src', ...).
Use class not id.
#largeImage{
top: 15%;
width:auto;
height: 83%;
position: fixed;
}
.portrait{
left: 36.36%;
}
.landscape{
left: 5%;
}
js
$('#largeImage').on('load', function () {
var that = $(this);
if (that.width() < that.height()) {
that.addClass('portrait');
} else {
that.addClass('landscape');
}
});
$('#thumbs').on('click', 'img', function () {
$('#largeImage').attr('src',$(this).attr('src').replace('thumb','large'));
});
I'd like to create an animation on a website to mimic a scrolling log file or tail -f. I'd feed it a list of fake log messages and they would be written to the bottom of the div and scroll up and off the top as new messages are displayed and then loop around. It needs to look authentic, white on black using a fixed width font etc.
Does anyone know of any javascript or jQuery libraries which could help me with this? I'm a beginner with javascript, so any advice on how to approach this would be much appreciated.
I've made a simple example for you
http://jsfiddle.net/manuel/zejCD/1/
// some demo data
for(var i=0; i<100; i++) {
$("<div />").text("log line " + i).appendTo("#tail")
}
// scroll to bottom on init
tailScroll();
// add button click
$("button").click(function(e) {
e.preventDefault();
$("<div />").text("new line").appendTo("#tail");
tailScroll();
});
// tail effect
function tailScroll() {
var height = $("#tail").get(0).scrollHeight;
$("#tail").animate({
scrollTop: height
}, 500);
}
#tail {
border: 1px solid blue;
height: 500px;
width: 500px;
overflow: hidden;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<div id="tail">
<div>some line of text</div>
</div>
<button>Add Line</button>
Here is a great solution
This uses an ajax request, and the HTTP Range: header to request only the last ~30KB of a log file. It then polls for data appended to that file, and only ever retrieves new data (no refreshing the whole file, or even the last 30KB). Handles file truncation too.
https://github.com/ukhas/js-logtail#readme
I've updated Manuel van Rijn's script to include a timer and a toggle switch, along with some minor changes to the log lines. hope this helps.
http://jsfiddle.net/5rLw3LoL/
html:
<div id="tail">
<div>some line of text</div>
</div>
<button>Add Line</button>
js:
var tailcounter = 100;
var tailswitch = false;
// scroll to bottom on init
tailScroll();
// add line to log
function tailappend() {
$("<div />").text("log line " + tailcounter).appendTo("#tail");
tailcounter++;
tailScroll();
}
// auto update every second
var t = setInterval(tailappend, 1000);
// toggle updates button click
$("button").click(function (e) {
e.preventDefault();
switch (tailswitch) {
case false:
clearInterval(t); // turns off auto update
tailswitch = true;
alert("auto update off");
break;
case true:
t = setInterval(tailappend, 1000); // restarts auto update
tailswitch = false;
alert("auto update on");
break;
}
});
// tail effect
function tailScroll() {
var height = $("#tail").get(0).scrollHeight;
$("#tail").animate({
scrollTop: height
}, 500);
}
css: (important for formatting)
#tail {
border: 1px solid blue;
height: 400px;
width: 500px;
overflow: hidden;
}
This can be achieved with CSS by simply flipping the outer and inner container using transform: rotateX(180deg); https://jsfiddle.net/tnrn6h59/2/
Only issue here is that the scroll is also reversed, not an issue for mobile.