Im trying to make a 'blanket' of divs containing child divs 150px high and 150px wide.
I want each child div to fade in 1 after the other after after a millisecond or so, opacity changing from 0, to 1.
I cant seem to figure out how this works, or how id do it though?
http://jsfiddle.net/CCawh/
JS
$(function(){
var figure = [];
w = 1500;
h = 450;
for(i = 0, i < 30, i++){
$('div').append(figure[].clone()).fadeIn();
}
});
Here is a working solution.
The problems in your code
in for(i = 0, i < 30, i++), you should use ';', not ',' . Use developer tools in your browser to catch such typos
In your code $('div').append(figure[].clone()).fadeIn(); , The fadeIn applies to $('div') as append() returns the calling object itself. You must replace it with $('<figure></figure>').appendTo('div').fadeIn('slow'); and to fadeIn items one by one you could set a timeout with incrementing delays
Add display: none; style to the figure to keep it hidden initially
Here is the full code.
$(function(){
for(i = 0; i < 30; i++){
setTimeout(function(){$('<figure></figure>').appendTo('div').fadeIn('slow');}, i*200);
}
});
Here is a fiddle to see it working http://jsfiddle.net/CCawh/12/
Try using greensock TweenLite http://www.greensock.com/get-started-js/.
It has staggerTo/staggerFrom action that does exactly what you are asking. TweenLite in conjunction with jQuery makes animation very easy.
This would be a possible solution (DEMO).
Use an immediate function and call it again n times in the fadeIn callback.
$(function(){
var figure = $('figure');
var counter = 0;
(function nextFade() {
counter++;
figure.clone().appendTo('div').hide().fadeIn(500, function() {
if(counter < 30) nextFade();
});
})();
});
You can use the following implementation as an example. Using setTimeout() will do the trick.
I've updated your jsfiddle here: http://jsfiddle.net/CCawh/5/
HTML:
<div class="container">
<div class="box"></div>
</div>
CSS:
.box {
display: none;
float: left;
margin: 10px;
width: 150px;
height: 150px;
background-color: #000;
}
JS:
$(function() {
var box = $('.box');
var delay = 100;
for (i = 0; i < 30; i++) {
setTimeout(function() {
var new_box = box.clone();
$('.container').append(new_box);
new_box.fadeIn();
}, delay);
delay += 500; // Delay the next box by an extra 500ms
}
});
Note that in order for the element to actually fade in, it must be hidden in the first place, i.e. display: none; or .hide()
Here's perhaps a more robust solution without counters:
http://jsfiddle.net/CCawh/6/
for(var i = 0; i < 30; i++){
$('div').append($('<figure>figure</figure>'));
}
(function fade(figure, duration) {
if (figure)
figure.fadeIn(duration, function() { fade(figure.next(), duration); });
})($('figure').first(), 400);
By the way, clauses in for loops are separated using semicolons, not commas.
Related
I am trying to set interval to a function that is only called when user scrolls below a certain height. My code return no errors and the function does not run either. However, I tried logging a random number at the end of the function and it doesn't so I think it has to do with my function. Take a look:
var firstString = ["This ", "is ", " me."];
var firstPara = document.querySelector("#firstPara");
var distanceSoFar = (document.body.scrollTop);
window.addEventListener("scroll", function() {
setInterval(slideIn, 450);
});
function slideIn() {
if (distanceSoFar > "130") {
for (var i = 0; i < firstString.length; i++) {
var stringOut = firstString.shift();
firstPara.innerHTML += stringOut;
console.log("5");
}
}
};
firstPara is just a paragraph in a div on the page. So the idea is to place some text in it on interval when a user scrolls into that view like so:
body {
height: 1000px;
}
div {
position: relative;
top: 700px;
}
div #firstPara {
border: 1px solid;
}
Part of your code is working. It handles the scroll event correctly and the slideIn function is called but the condition distanceSoFar > "130" is never met.
I'd suggest two changes to make your code work as you expect:
Use document.documentElement.scrollTop instead of document.body.scrollTop. document.body.scrollTop may return incorrect values (0) on some browsers. Look at this answer, for example.
Declare distanceSofar inside of the slideIn function. You declared the variable on the top of your code, so it stores a static value of the scrollTop property.
I'd avoid using setInterval inside a scroll event handler, you are setting a lot of intervals and not clearing them. I added some console.logs to show you how the slideIn function keeps being called even when the user is not scrolling.
A final tip: the scrollTop property is a number, so you can compare it to 130 instead of "130".
Here is the working fiddle.
I tried your code. I think it is working as you expected. I also added a clearInterval inorder to clear the timer after printing all text and also to avoid repeated calling.
<html>
<head>
<style>
body {
height: 1000px;
}
div {
position: relative;
top: 700px;
}
div #firstPara {
border: 1px solid;
}
</style>
<script>
function start(){
var s =0;
var interval = undefined;
function slideIn() {
console.log(distanceSoFar);
if (distanceSoFar > "130") {
while ( firstString.length > 0) {
var stringOut = firstString.shift();
firstPara.innerHTML += stringOut;
console.log(s++);
}
clearInterval(interval);
interval = undefined;
}
};
var firstString = ["This ", "is ", " me."];
var firstPara = document.querySelector("#firstPara");
var distanceSoFar = (document.body.scrollTop);
window.addEventListener("scroll", function() {
if(!interval)
interval = setInterval(slideIn, 450);
});
};
</script>
</head>
<body onload="start()">
<div id="firstPara"/>
</body>
<html>
I'm trying to create a simple slideshow effect. I have 10 images, and I've created a basic HTML page with 2 buttons to go to the right or left image. On clicking the button, the images change.
Now, I'm trying to add a basic fade functionality to the changing image. But the fade effect isn't getting displayed. When I put alerts, I notice that the fade is taking place, but without the alerts it is too fast to be visible. Also, it is happening on the previous image, instead of the next one.
<html>
<head>
<style>
.main {
text-align: center;
}
.centered {
display: inline-block;
}
#image {
border: solid 2px;
width: 500px;
height: 500px;
}
#number {
font-size: 30px;
}
</style>
<script>
function goLeft() {
var image = document.getElementById("image");
var pos = document.getElementById("number");
if(Number(pos.innerHTML)==1) {
image.src = "Images\\10.jpg"
pos.innerHTML = 10;
} else {
image.src = "Images\\" + (Number(pos.innerHTML)-1).toString() + ".jpg"
pos.innerHTML = (Number(pos.innerHTML)-1).toString();
}
for (var i=0; i<25; i++) {
setTimeout(changeOpacity(image, i), 1000);
}
}
function changeOpacity(image, i) {
alert(parseFloat(i*4/100).toString());
image.style.opacity = (parseFloat(i*4/100).toString()).toString();
}
function goRight() {
var image = document.getElementById("image");
var pos = document.getElementById("number");
if(Number(pos.innerHTML)==10) {
image.src = "Images\\1.jpg"
pos.innerHTML = 1;
} else {
image.src = "Images\\" + (Number(pos.innerHTML)+1).toString() + ".jpg"
pos.innerHTML = (Number(pos.innerHTML)+1).toString();
}
for (var i=0; i<25; i++) {
setTimeout(changeOpacity(image, i), 1000);
}
}
</script>
</head>
<body>
<div class="main">
<div class="centered">
<img id="image" src="Images\1.jpg">
</div>
</div>
<div class="main">
<div class="centered">
<span id="number">1</span>
</div>
</div>
<div class="main">
<div class="centered">
<button onclick="goLeft()" style="margin-right:50px;">Go Left</button>
<button onclick="goRight()" style="margin-left:50px;">Go Right</button>
</div>
</div>
</body>
The problem is this block of code that is in your goLeft method, and goRight method:
for (var i=0; i<25; i++) {
setTimeout(changeOpacity(image, i), 1000);
}
You are creating 25 timers that, and each timer will execute approximately 1 second later.
Creating animations is best left to the CSS.
In your CSS add:
#image {
transition: opacity 0.5s ease;
}
And then in your JavaScript, simply: image.style.opacity = 1.0;
When the opacity changes, CSS will automatically transition the opacity length at the speed defined in the css, e.g 0.5s. Feel free to experiment.
I also added a jsfiddle here: http://jsfiddle.net/dya7L8wq/
You misunderstood setTimeout and the for loop.
Norman's answer provides a good solution with CSS, but he doesn't talk too much about why your code is not working. So I'd like to explain.
for (var i=0; i<25; i++) {
setTimeout(changeOpacity(image, i), 1000);
}
You assumption is:
invoke changeOpacity(image, 0) after 1 second
invoke changeOpacity(image, 1) 1 second after step 1
invoke changeOpacity(image, 2) 1 second after step 2
invoke changeOpacity(image, 3) 1 second after step 3
....
And the last step is invoking changeOpacity(image, 24) 1 second after previous step.
What actually happens is:
The loop is finished almost immediately!
In each iteration, setTimeout queues an asynchronous function invocation, and it's done! That says, it will return right away, rather than wait until changeOpacity returns.
And then, after about 1 second, changeOpacity fires 25 times almost at the same time, because you queued it 25 times in the for loop.
Another problem here is: in changeOpacity invocations, passed-in parameter i are not 1, 2, 3...., they all have the same value that causes for loop to exit (1 second ago) - 25, because JS doesn't have a block scope prior to ES6 (in ES6 we have keyword let for it).
In a pure JS solution, to ensure the time sequence we'd usually queue next invocation at the end of every step:
function changeOpacity() {
// do something here
// before the function returns, set up a future invocation
setTimeout(changeOpacity, 1000)
}
Here's an example to print a list of numbers from 1 to 5:
var go = document.getElementById('go')
var op = document.getElementById('output')
var i = 0
function printNum() {
var p = document.createElement('p')
p.innerHTML = ++i
op.appendChild(p)
// next step
if(i < 5) {
setTimeout(printNum, 500)
}
}
go.onclick = printNum
<button id="go">GO</button>
<div id="output"></div>
Why use pure JavaScript?
Use jQuery.
It has a pretty neat fadeTo() function and a useful fadeIn() function.
Might wanna use that ;)
I want to make a box disappear and reappear alternatively by using the loop. The problem is that the box does not appear at all though the loop runs until i=10. Can someone explain this?
for(var i=0;i<10;i++){
if(document.getElementById("box").style.display=="none"){
document.getElementById("box").style.display="block";}
else{
document.getElementById("box").style.display="none";
}
console.log(i);
}
The simplest explanation is that the loop iteration finishes before the rendering takes place, and you only get the end result.
See this modified version of your code, it's kind of forcing the drawing by using timeouts:
for (var i = 0; i < 10; i++) {
setTimeout(toggle, i * 100);
}
function toggle() {
if (document.getElementById("box").style.display == "none") {
document.getElementById("box").style.display = "block";
} else {
document.getElementById("box").style.display = "none";
}
}
#box {
width: 50px;
height: 50px;
background: #eee;
}
<div id="box"></div>
Usually when you loop simply with (while, for, etc ...) it will run in a clock-cicle(nano-seconds, or milli-seconds) ...
For the computer, your box is appearing and disappearing. But not for humans, simply because it's too fast.
I suggest you to try you algorithm with some Javascript animations, like this one
http://www.w3schools.com/jquery/eff_fadein.asp
I am making an info screen, and for that, it needs to show reviews from their customers pulled from Trustpilot.
I got the reviews and everything formatted in HTML showing the 20 latest, but I want to present it very sweet. I am not a JavaScript guru, but I thought i would do it using jQuery and its fadein function.
What is want, is have 20 unique divs fading in with X milliseconds difference popping randomly up. By unique I mean, that each div must have unique content. And by randomly popping up, I mean that if box 1 spawns first, then the next should be 5, then 14 etc, and then another cycle the next time around.
Just like what I made here;
$(function() {
var box = $('.box');
var delay = 100;
for (i = 0; i < 30; i++) {
setTimeout(function() {
var new_box = box.clone();
$('.container').append(new_box);
new_box.fadeIn();
}, delay);
delay += 500; // Delay the next box by an extra 500ms
}
});
http://jsfiddle.net/CCawh/5/
Is this even possible, and how would this be done?
I am very new to JavaScript, so please bear with me if I ask to much
Thanks in advance.
EDIT:
The HTML i want to spawn will all be wrapped in divs, so it would go like this;
<div id="one">content</div>
<div id="two">content</div>
<div id="three">content</div>
<div id="four">content</div>
etc.
Made up a nice function for you. I believe this may be what you are looking for
Here's a rundown of how it works :
Populate an array with numbers randomly generated 1-10 in this case.
Run through that array with a set interval, and when everything has
been added stop the interval
pretty straightforward from there. Set the visibility etc. You should be able to change up the function to dynamically add HTML elements and what-not, but just giving you something to start with.
var usedNum = [];
var i, j, y;
i = 0;
for(y = 0; y < 10; y++){
var x = Math.floor((Math.random() * 10) + 1);
if(!isUsed(x)) usedNum.push(x);
else y--;
}
var showInterval = setInterval ( function(){
if(i == 10){
clearInterval(showInterval);
}
$(".container div[data-line='" + usedNum[i] + "']").css({opacity: 0.0, visibility: "visible"}).animate({opacity: 1.0});
i++;
}, 500);
function isUsed(num) {
var used = false;
for(j = 0; j < usedNum.length; j++){
if(usedNum[j] == num){
used = true;
}
}
return used;
}
Demo fiddle : http://jsfiddle.net/xS39F/3/
Edit:
You can also mess around with the speed of the animation. In this demo (http://jsfiddle.net/adjit/XYU34/1/) I set the speed to 1000 so the next element starts fading in before the last element was done fading in. Makes it look a little smoother.
Instead of using a for loop and setTimeout, would setInterval work better for what you need? Some HTML might help better understand what you're trying to achieve.
$(function() {
var box = $('.box');
var delay = 100;
var interval = setInterval(function() {
var new_box = box.clone();
$('.container').append(new_box);
new_box.fadeIn();
}, delay);
delay += 500; // Delay the next box by an extra 500ms
}, delay);
});
The HTML structure is like this
<ul class="innerfade">
<li style="position: absolute; z-index: 4; display: none;">some Text</li>
<li style="position: absolute; z-index: 3; display: none;">bla bla bla</li>
<li style="position: absolute; z-index: 2; display: none;">bla bla</li>
<li style="position: absolute; z-index: 1; display: none;">some Text</li>
<ul>
I wanna change the css of each <li> from display:none to display:block to none again after an interval. And this goes on in an endless loop. Can someone tell me how to acheive this in jquery.
So far my Jquery look like this -
$('.innerfade li').each(function()
{
$(this).css('display', 'block');
$(this).fadeOut('slow');
});
I tested this on firebug console but it didn't work. And i didnt go ahead and add the setTimout function.
Anyway any Help will be greatly appreciated!
Edit: I have edited the code so i can explain better what i'm trying to acheive. Like you can see each li is one below the other. The li's contain pictures and some text in the same structure(which i have omitted from here to keep things simple). Hence i want only one li to display at a time and then fade out. N then the next li takes over n so on and so forth in an endless loop. And i want each li to stay alive for roughly 5 mins
DEMO
var el = $('.innerfade li'),
i = 0;
$(el[0]).show();
(function loop() {
el.delay(1000).fadeOut(300).eq(++i%el.length).fadeIn(500, loop);
}());
Edit:
This code was written way too late at night by a tired programmer (myself), and should not be used due to browser hosing. Please see jQuery draws to a halt on Chrome and mac OS for production-quality code!
Do not use the below code.
Use two mutually-dependent functions:
var $lis = $('ul.innerfade > li');
function fadeThemOut()
{
$lis.fadeOut('slow', fadeThemIn);
}
function fadeThemIn()
{
$lis.fadeIn('slow', fadeThemOut);
}
// kick it off
fadeThemOut();
Demo: http://jsfiddle.net/mattball/nWWSa/
You can write this more concisely using .fadeToggle():
var $lis = $('ul.innerfade > li');
function toggleThem()
{
$lis.fadeToggle('slow', toggleThem);
}
// kick it off
toggleThem();
Demo: http://jsfiddle.net/mattball/XdAEG/
Try this
setInterval(function(){
$(".innerfade li").fadeToggle();
}, 1000);
Edit: Based on your clarification of what you are trying to achieve:
(function () {
var i = 0;
var delay = 1000 * 60 * 5; // 5 minutes
var items = $(".innerfade li");
var len = items.length;
setInterval(function () {
items.fadeOut().eq(++i % len).fadeIn();
}, delay);
})();
The above gives you a cross-fade effect. If you want to completely fade out before fading in the next element, you want this:
(function () {
var i = 0;
var delay = 1000 * 60 * 5; // 5 minutes
var items = $(".innerfade li");
items.eq(0).show();
var len = items.length;
setInterval(function () {
items.filter(":visible").fadeOut(function() {
items.eq(++i % len).fadeIn();
});
}, delay);
})();
http://jsfiddle.net/gilly3/CDHJY/
jQuery uses CSS-Selectors. What you are doing is trying to get all li-tags inside an innerfade-tag, which obviously doesn't exist.
You need to select it using its class, just like in CSS:
$(".innerface li")...
Although not fit with your Endless Loopm but this is a Loop where you stop at the Endpoint
var el = $('.innerfade li'), i = 0; $(el[0]).fadeIn();<BR> (function loop() { if(i+1<4){ el.delay(1000).fadeOut(300).eq(++i%el.length).fadeIn(500, loop);<BR>} else el.delay(1500).fadeOut(1000); <BR>} ());
try this:
$(function() {
$('.innerfade li').each(function() {
blink($(this))
});
});
function blink(li) {
li.fadeOut('slow', function() {
li.fadeIn('slow', blink(li));
});
}
Check out this fiddle.