Javascript fadein on mouseover works but doesn't fadeout - javascript

So real simply, I have figured out how to fade a div in on a mouseover call. But I want to know how to fade it out without simply duplicating the javascript opposite of what it already is and linking that to a onmouseout.
Here is my Javascript:
<script type="text/javascript">
function fadein(objectID){
object = document.getElementById(objectID);
object.style.opacity = '0';
animatefadein = function (){
if(object.style.opacity < 1){
var current = Number(object.style.opacity);
var newopac = current + 0.1;
object.style.opacity = String(newopac);
setTimeout('animatefadein()', 100);
}
}
animatefadein();
}
and my html
<div id="rolloverwrapper" style="opacity:0;"></div>
<div id="wrapper">
<div id="content">
<div id="button">
<img src="images/dj.png" onmouseover="fadein('rolloverwrapper');"/>
</div>
</div>
</div>

Try something like this:
<script type="text/javascript">
function fade(objectID, amount) {
var MIN_OPACITY = 0;
var MAX_OPACITY = 1;
object = document.getElementById(objectID);
animatefade = function() {
if(object.style.opacity < MAX_OPACITY && object.style.opacity > MIN_OPACITY){
var current = Number(object.style.opacity);
var newopac = current + amount;
object.style.opacity = String(newopac);
setTimeout('animatefade()', 100);
}
}
animatefade();
}
</script>
With the following HTML:
<img src="images/dj.png" onmouseover="fade('rolloverwrapper', 0.1);" onmouseout="fade('rolloverwrapper', -0.1);"/>

If the behavior you want is the opposite of what you already have, but on a different event, then simply do it. Don't look for fancy solutions when you know a simple one already and it works.

Add a parameter to your fadein function to specify the fade direction. 1/-1, 0/1, t/f, etc... and pass that in to your animatefadein.
Then you'd have
<img src="..." onmouseover="fadein('rolloverwrapper', 1)" onmouseout="fadein('rolloverwrapper, 0)" />
However, you should look into using jquery for this sort thing. The library would be a "heavy" compared to just these few lines of JS, but the flexibility you gain is vast.

Related

How to call a function in external script file from HTML

I'm trying to call a javascript function in my HTML index file and I can't get it to work.
This is my html file that I'm trying to call a function from.
<div class="main">
<h1 class="header-main" onload="HeaderTyper('Welcome', this)">
<noscript>no javascript</noscript>
</h1>
</div>
<script type="text/javascript" src="script.js"></script>
And this is the script.
function HeaderTyper(message, element){
var i = 0;
var speed = 50;
if (i < message.length) {
element.innerHTML += message.charAt(i);
//play keystroke sound
i++;
setTimeout(HeaderTyper, speed);
}
}
I'm trying to get a typewriter effect style header. I'm planning to add some keystroke sounds, but first I need to figure out how to actually type it out in the header tag. The code won't type out the message I'm passing in argument. What did I do wrong ? Thank you for any help.
After the HTML page ends (As #johannchopin explained), import the file and then add an event listener (as #aaronburrows explained).
<body>
<div class="main">
<h1 class="header-main">
<noscript>no javascript</noscript>
</h1>
</div>
</body>
</html>
<script type="text/javascript" src="script.js"></script>
<script>
let h1 = document.querySelector('.header-main');
h1.addEventListener('load', HeaderTyper("Welcome", h1, false));
</script>
Also, I fixed the function, it was missing the parameters.
function HeaderTyper(message, element, i) {
var speed = 50;
if (i < message.length) {
console.log(message.charAt(i))
element.innerHTML += message.charAt(i);
//play keystroke sound
setTimeout(function(){ HeaderTyper(message,element,++i)}, speed);
}
}
You're attempting to bind a function call before it is loaded into the browser. Remove the onload from the HTML and add an event listener to the script.
According to this solution, The onload event can only be used on the document(body) itself. Best way to achieve this is to call the function in a <script> tag just before the </body> closing tag:
<div class="main">
<h1 class="header-main">
<noscript>no javascript</noscript>
</h1>
</div>
<script>
function HeaderTyper(message) {
var i = 0;
var speed = 50;
var element = document.querySelector('.header-main');
if (i < message.length) {
element.innerHTML += message.charAt(i);
//play keystroke sound
i++;
setTimeout(HeaderTyper, speed);
}
}
HeaderTyper('Welcome');
</script>
Ok, hi there.
function HeaderTyper(message, element){
alert('script loaded') //<---
var i = 0;
I put this line at the beginning of the script to make sure it works. And it's not.
Why?
Because you just made your function but doesn't call it.
First way to solve this - put ur function in the "script" of HTML doc. And call it after, like
<script>
function HeaderTyper(message) {
let i = 0
let speed = 50
let element = document.querySelector('.header-main')
if (i < message.length) {
element.innerHTML += message.charAt(i)
i += 1
setTimeout(HeaderTyper, speed)
}
}
HeaderTyper('Welcome') //<---
</script>
Second way - put HeaderTyper() at the end of script.js file, so the function start, but you need to make a link for "message" and "element".
setTimeout(HeaderTyper, speed);
}
}
HeaderTyper(someMessage, someElement) //<---

Generate array of image in javascript inside <div>

I need to make the background image in div tag and it has to change automatically, I already put the array of images inside the javascript, but the images is not showing when i'm run the site.The background should behind the menu header.
This is the div
<div style="min-height:1000px;position:relative;" id="home">
below of the div is containing the logo, menu and nav part.
<div class="container">
<div class="fixed-header">
<!--logo-->
<div class="logo" >
<a href="index.html">
<img src="images/logo.png" alt="logo mazmida" height="142" width="242">
</a>
</div>
<!--//logo-->
This is the javascript
<script>
var imgArray = [
'images/1.jpg',
'images/2.jpg',
'images/3.jpg'],
curIndex = 0;
imgDuration = 2000;
function slideShow() {
document.getElementID('home').src = imgArray[curIndex];
curIndex++;
if (curIndex == imgArray.length) { curIndex = 0; }
setTimeout("slideShow()", imgDuration);
}
slideShow();
You have a few issues with your script. I've made a live JSbin example here:
https://jsbin.com/welifusomi/edit?html,output
<script>
var imgArray = [
'https://upload.wikimedia.org/wikipedia/en/thumb/0/02/Homer_Simpson_2006.png/220px-Homer_Simpson_2006.png',
'https://upload.wikimedia.org/wikipedia/en/thumb/0/0b/Marge_Simpson.png/220px-Marge_Simpson.png',
'https://upload.wikimedia.org/wikipedia/en/a/aa/Bart_Simpson_200px.png'
];
var curIndex = 0;
var imgDuration = 1000;
var el = document.getElementById('home');
function slideShow() {
el.style.backgroundImage = 'url(' + imgArray[curIndex % 3] + ')';
curIndex++;
setTimeout("slideShow()", imgDuration);
}
slideShow();
</script>
There are a few issues with your script:
On the element since it's a div not an img, you need to set style.backgroundImage instead of src. Look at https://developer.mozilla.org/en-US/docs/Web/CSS/background for other attributes to related to background image CSS
Also it's document.getElementById
Optimizations
And you can use mod % trick to avoid zero reset
Use setInterval instead of setTimeout
Further optimzations
Use requestAnimationFrame instead of setTimeout/setInterval
I suggest getting familiar with your browser debugging tools which would help identify many of the issues you face.
document.getElementID('home').src = imgArray[curIndex]
You are targeting a div with an ID of home, but this is not an Image element (ie ,
But since you want to alter the background colour of the DIV, then you use querySelector using javascript and store it in a variable, then you can target the background property of this div (ie Background colour).
I hope this helps.
You are trying to change the src property of a div, but divs do not have such property.
Try this:
document.getElementById('home').style.backgroundImage = "url('" + imgArray[curIndex] + "')"
This changes the style of the target div, more precisely the image to be used as background.
As you want to change the background image of the div, instead of document.getElementID('home').src = imgArray[curIndex] use
document.getElementById("#home").style.backgroundImage = "url('imageArray[curIndex]')";
in JavaScript or
$('#home').css('background-image', 'url("' + imageArray[curIndex] + '")'); in jquery.
To achieve expected result, use below option of using setInterval
Please correct below syntax errors
document.getElementID to document.getElementById
.src attribute is not available on div tags
Create img element and add src to it
Finally use setInterval instead of setTimeout outside slideShow function
var imgArray = [
'http://www.w3schools.com/w3css/img_avatar3.png',
'https://tse2.mm.bing.net/th?id=OIP.ySEgAgJIlDQsIQTu_MeoLwHaHa&pid=15.1&P=0&w=300&h=300',
'https://tse4.mm.bing.net/th?id=OIP.wBAPnR04OfXaHuFI9Ny2bgHaE8&pid=15.1&P=0&w=243&h=163'],
curIndex = 0;
imgDuration = 2000;
var home = document.getElementById('home')
var image = document.createElement('img')
function slideShow() {
if(curIndex != imgArray.length-1) {
image.src = imgArray[curIndex];
home.appendChild(image)
curIndex++;
}else{
curIndex = 0;
}
}
setInterval(slideShow,2000)
<div style="position:relative;" id="home"></div>
code sample - https://codepen.io/nagasai/pen/JLKvME

setTimeout not working, other methods of queuing in a for loop?

Code below (the divs are shaded in my real example, I want to sequentially decrease their opacity to 0 so each disappears, in order.
I tried to doing this without using setTimeout, but all of the divs disappeared simultaneously - its good to know that the part of the code that changes the opacity works, but I cant seem to get them to work sequentially.
When I try to use setTimeout (which I presume I am implementing incorrectly),nothing happens!
Any help would be really appreciated with this, I'm fairly new to JavaScript and haven't touched it in a while and tutorials haven't been able to help me.
<body>
<div id="div1"></div>
<div id="div2"></div>
<div id="div3"></div>
<div id="div4"></div>
<script type="text/javascript">
// the divs that we want to cycle through are named here.
var divs = ["#div1", "#div2", "#div3", "#div4"];
var divsLength = divs.length;
for (var i = 0; i < divsLength; i++) {
setTimeout(function(){
$(divs[i]).fadeTo(1000, 0, function() {
});
},1500);
};
</script>
</body>
Here's a way you should be able to do this without setTimeout:
function doFade(items, index) {
$(items[index]).fadeTo(1000, 0, function() {
doFade(items, index + 1);
});
}
doFade(divs, 0);
If you're targetting browsers that support ES5 (most modern versions do), then you can further simplify doFade:
function doFade(items, index) {
$(items[index]).fadeTo(1000, 0, doFade.bind(this, items, index + 1));
}
working jsfiddle
You can use a recursive function to do that kind of thing, something like that :
function seqFade($el){
$el.first().fadeOut(500, function(){ //Take the first element and fade it out
seqFade($el.slice(1)); //Recall the function when complete with the same set of element minus the first one.
})
}
seqFade($('div')); //Call the function
http://jsfiddle.net/L2fvdfy2/
In your code, it could look like that :
function seqFade($el){
$el.first().fadeOut(500, function(){
seqFade($el.slice(1));
})
}
seqFade($('#div1, #div2, #div3, #div4'));
It's because when the timeout finally fires the variable "i" only has the last index value. Also the loop will start all the timeouts at almost the same time.
There are other ways to accomplish it but this might work with minimal changes to your code.
Try this:
<script type="text/javascript">
var divs = ["#div1", "#div2", "#div3", "#div4"];
var divsLength = divs.length;
for (var i = 0; i < divsLength; i++) {
setTimeout((function(index) {
return function(){
$(divs[index]).fadeTo(1000, 0, function() { });
}
)(i)),1500 + (i * 1500));
};
</script>
</body>
This will create an instance of the function with it's own copy of the index when it was called. Also increasing the timeout of each timeout will have them execute sequentially.
try this:
// the divs that we want to cycle through are named here.
var divs = ["#div1", "#div2", "#div3", "#div4"];
(function fade(i) {
$(divs[i]).fadeTo(1000, 0, function() {
setTimeout(function() {fade(++i);}, 500);
});
})(0);
for (var i = 1; i <= divsLength; i++) {
setTimeout(function(){
$(divs[i]).fadeTo(1000, 0, function() {
});
},1000*i);
lets try this

Switch content of DIV with another set DIVs with a timer

I have 3 divs in a html page, 2 divs should be hiddent always but theire content should be displayed in another div and this content should be changed every x seconds. Hows that possible using jquery/javascript?
<div id="contentA">
<!-- Some contents goes here, and it should be hidden -->
</div>
<div id="contentB">
<!-- Some contents goes here, and it should be hidden -->
</div>
<div id="displayArea">
<!-- switch between contentA and contentB on a timer say every 5 seconds -->
</div>
Do not use the .html() function to copy content from one place to another. HTML is a serialisation format designed to carry DOM structures from a server to a client. Once the page is in a DOM structure you should manipulate that DOM structure directly using DOM methods. Using .html() to serialise a DOM node and then recreate it somewhere else risks losing things like event handlers, other hidden data, etc.
On that basis, to copy the current contents of a div into another:
var $contents = $('#contentA').contents().clone(); // copy the source element's contents
$('#displayArea').empty().append($contents); // drop them into the destination
In full:
(function() {
var delay = 3000;
var state = 0;
(function next() {
state = 1 - state;
var src = state ? '#contentA' : '#contentB';
var $contents = $(src).contents().clone();
$('#displayArea').empty().append($contents);
setTimeout(next, delay);
})();
})();
Try this :)
<div id='a' style='display: none;'>this is a</div>
<div id='b' style='display: none;'>this is b</div>
<div id='show'></div>
<script>
$(document).ready(function(){
var count = 0;
var content = '';
var j = setInterval(function () {
count++;
if(count%2===0){
content = $('#a').html();
}else{
content = $('#b').html();
}
$('#show').html(content);
}, 5000);
});
</script>
Try this:
var toggle = false;
$("#displayArea").html($("#contentA").html());
setInterval(function() {
$("#displayArea").html(toggle ? $("#contentA").html() : $("#contentB").html());
toggle = !toggle;
}, 5000);
Working DEMO
I don't know if this is what you need but this script should work:
check = true;
$(document).ready(function(){
setInterval(function(){
if(check) {
check = false;
$('#displayArea').html("a");
}
else {
check = true
$('#displayArea').html("b");
}
}, 5000);
});
function doSlides() {
var msg = messages.shift();
messages.push(msg);
$('#displayArea').html(msg);
};
var messages = [
$('#contentA').find('p').html(),
$('#contentB').find('p').html()
];
Demo:
http://jsfiddle.net/8Ux3L/
Here's one way to do it using setInterval():
var divs = $('div[id^="content"]').hide(),
i = 0;
function cycle() {
$("#displayArea").html(divs.eq(i).html());
i = ++i % divs.length; // increment i, and reset to 0 when it equals divs.length
}
setInterval(cycle, 2000); //Cycle every 2 seconds
Wrapping in a self executing function:
(function cycle() {
$("#displayArea").html(divs.eq(i).html());
i = ++i % divs.length; // increment i, and reset to 0 when it equals divs.length
setTimeout(cycle, 2000);
})();
DEMO
Try following code
<!DOCTYPE html>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js" ></script>
<script>
var divSelected = "A";
function switch1()
{
if (divSelected == "A")
{
$("#displayArea").text($("#contentA").text());
divSelected = "B";
}
else
{
$("#displayArea").text($("#contentB").text());
divSelected = "A";
}
}
$(document).ready(function()
{
var test = setInterval( "switch1()" , 5000);
});
</script>
</head>
<body>
<div id="contentA" style = "display:none;">
Contect A
</div>
<div id="contentB" style = "display:none;">
Content B
</div>
<div id="displayArea">
</div>
</body>
</html>
Use an interval to trigger a function every x seconds, then jQuery replaceWith to swap the divs. If you don't want to replace the actual node but just the contents, then .html() is probably the way to go.

Javascript jquery fade-in/fadeout loop, how to use timer?

New to javascript and such, trying to create a loop for fading logos using jquery.
I've got it cycling through them just fine. But i tried to make the loop continuous; so that when it reached the last logo it went back to the beginning, by resetting my for-counter to 0 every time it reached the last logo. This resulted in an infinite loop i think that crashed my browser. So i did a quick google and discovered the window.setInterval(...) timer function.
My problem is, now that firing the looping code relies on timing, i can't figure out how to calculate the interval time. For reference here's the code that fades the logos in and out (before trying to loop it):
$(document).ready(function (){
var fadeDuration = 1000;
var timeBetweenFade = 2000;
var totalTimePerChange = fadeDuration + timeBetweenFade;
var totalLogos = $('.logo').length;
var currentLogo;
var i;
for(i = 0; i < totalLogos; i++)
{
currentLogo = "#img" + i;
if(i == 0){
$(currentLogo).fadeIn(fadeDuration).delay(timeBetweenFade).fadeOut(fadeDuration);
}
else{ //general case
$(currentLogo).delay(totalTimePerChange * i).fadeIn(fadeDuration).delay(timeBetweenFade).fadeOut(fadeDuration);
}
}
});
I tried to get the time a complete loop took in a couple of ways:
$(document).ready(function (){
//..declarations..
window.setInterval( function() {
//..FOR LOOP HERE..
}, i*(fadeDuration + timeBetweenFade + fadeDuration));
});
//I also tried..
$(document).ready(function (){
//..declarations..
var timeTakenToLoop;
var startLoopTime;
window.setInterval( function() {
startLoopTime = new Date().getTime();
//...FOR LOOP HERE..
timeTakenToLoop = new Date().getTime() - startLoopTime;
}, timeTakenToLoop);
});
But in both cases I get logos starting to overlap as the function calls timing is wrong. Could someone with a bit more experience suggest what the best approach would be?
Oh and just in case anyone needs it to understand the javascript, here's the html to match..
<div id="img0" class="logo">
<img src="{% static "CSS/Images/phone_icon.gif" %}"/>
</div>
<div id="img1" class="logo">
<img src="{% static "CSS/Images/email_icon.gif" %}"/>
</div>
<div id="img2" class="logo">I can fade too</div>
Simple jQuery approach, no setTimeout and no setInterval.
var loop = function(idx, totalLogos) {
var currentLogo = "#img" + idx;
$(currentLogo)
.delay(currentLogo)
.fadeIn(fadeDuration)
.delay(currentLogo)
.fadeOut(fadeDuration, function(){
loop( (idx + 1) % totalLogos, totalLogos);
});
}
loop(0, $('.logo').length);​
See it here.

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