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How to Fade Out an element using Javascript

I have a loading page that I used javascript to make. I would like to be able to fade-out the loading page as the index.html fades in. I understand this can easily be done with jQuery, but would like to not use jQuery since I have yet to use it on this site. I understand this may be a common question, but I have not been able to tailor other answers to my solution since most use jQuery.
I am thinking to edit the opacity of the loading element onReady. Or could I do this with simple CSS?
Javascript:
function onReady(callback) {
var intervalID = window.setInterval(checkReady, 1000);
function checkReady() {
if (document.getElementsByTagName('body')[0] !== undefined) {
window.clearInterval(intervalID);
callback.call(this);
}
}
}
function show(id, value) {
document.getElementById(id).style.display = value ? 'block' : 'none';
}
onReady(function () {
show('page', true);
show('loading', false);
});
HTML:
<div id="loading">
<div class="logo">
Logo
</div>
<span class="loading-center-cross"></span>
<h3>Loading...</h3>
</div>
<div id="page">
.....
</div>
I expect for the loading screen to fade to the index.html as previously described. Thanks for all the help!

You can do this with CSS, using something like the following:
function onReady(callback) {
var intervalID = window.setInterval(checkReady, 1000);
function checkReady() {
if (document.getElementsByTagName('body')[0] !== undefined) {
window.clearInterval(intervalID);
callback.call(this);
}
}
}
function show(id, value) {
document.getElementById(id).classList.toggle('fade-in-out', value);
}
onReady(function () {
show('page', true);
show('loading', false);
});
And have the following CSS:
#page,
#loading {
transition: opacity 1s;
}
.fade-in-out {
opacity: 0;
pointer-events: none;
}
That way, the show() function will toggle a class of fade-in-out based on value, and there will be a transition to 'fade' the div in and out, with an addition of pointer-events: none to make the div non-interactive whist transitioning.

not able to move scroll bar inside a div

I have a div that gets filled dynamically when the user sends data from form, it is similar to chat box. where the user ends message and that message gets displayed inside the div. Now this div has a scroll bar that should stay at the bottom but if the user scrolls then it should stay at that position where the user has kept it
The issue is that although the scroll bar stays at the bottom but when the user pulls it up, then also it pulls itself to bottom and the user can't use it to scroll.
Code for div
var youInterval;
function startInterval() {
youInterval = setInterval(function() {
var elem = document.getElementById('scrollbody');
elem.scrollTop = elem.scrollHeight;
}, 500);
}
document.addEventListener('scroll', function(event) {
if (event.target.id === 'scrollBottom') {
clearInterval(youInterval);
}
}, true);
startInterval();
.chatbox__body {
overflow-y: auto;
}
<div class="chatbox__body" id="scrollbody"></div>
Can anyone please help me with the issue

Your condition here is failing if (event.target.id === 'scrollBottom') {
The event generated by scroll is on document so, event.target.id is actually checking id property of document which is not there.
You have to disable overflow in body first and then add overflow to div
html,body{ height:100%; width:100%;overflow:hidden;}
.chatbox__body {
overflow-y: auto;
height:100%;
}
In your JS check for if (event.target.id === 'scrollbody') {
SNIPPET
var youInterval;
function startInterval() {
youInterval = setInterval(function() {
var elem = document.getElementById('scrollbody');
elem.scrollTop = elem.scrollHeight;
}, 500);
}
document.addEventListener('scroll', function(event) {
debugger;
if (event.target.id === 'scrollbody') {
clearInterval(youInterval);
}
}, true);
startInterval();
html,body{ height:100%; width:100%;overflow:hidden;}
.chatbox__body {
overflow-y: auto;
height:100%;
}
#content{
height:200%;
width:100%;
background-color:red;
}
<div class="chatbox__body" id="scrollbody">
<div id="content"></div>
</div>

Wait for element to be displayed to user

How do I wait for an element to be displayed/seen by the user? I have the following function, but it only checks to see if the element exists and not whether it is visible to the user.
function waitForElementDisplay (selector, time) {
if (document.querySelector(selector) != null) {
return true;
} else if (timeLimit < timeSince) {
return false;
} else {
timeSince += time;
setTimeout(function () {
waitForElementDisplay(selector, time, timeLimit, timeSince);
}, time);
}
}

It's a bit confuse, are you trying a simple "sleep"?
You can wait element load using:
document.querySelector(selector).onload = function() {
// Your code ...
}
Some working snippet, run it:
// Triggering load of some element
document.querySelector("body").onload = function() {
// Setting the timeout and visible to another element
setTimeout(function () {
document.querySelector("#my_element").style.display = "block" /* VISIBLE */
}, 1000);
}
#my_element{
width: 100px;
height: 100px;
background-color: red;
display: none; /* INVISIBLE */
}
<div id="my_element"></div>
If you want to wait time as you have set to the function and the selector which should appear after this time.. You can mind about a simple setTimeout() and CSS.
Run the example below, hope it helps:
// Triggering, in my exemple i've used: WINDOW ONLOAD
window.onload = function() {
waitForElementDisplay("#my_element", 1000);
}
function waitForElementDisplay (selector, time) {
// Check the DOM Node in console
console.log(document.querySelector(selector));
// If it's a valid object
if (typeof document.querySelector(selector) !== "undifined") {
// Setting the timeout
setTimeout(function () {
document.querySelector(selector).style.display = "block" /* VISIBLE */
}, time);
}
}
#my_element{
width: 100px;
height: 100px;
background-color: red;
display: none; /* INVISIBLE */
}
<div id="my_element"></div>

You could use jQuery .ready()
selector.ready(function(){
// do stuff
})

setInterval + image src changes when clicked on button

I want to give blink effect(dark and light) when clicked on the button.I have written the following code but it does not work.So please help me.
$(document).ready(function () {
$(".search").click(function () {
setInterval(function () {
var curSrc = $("#red").attr('src');
if (curSrc === '../images/lightred.jpg') {
$(curSrc).attr("src", "../images/Darkred.jpg");
}
if (curSrc === '../images/Darkred.jpg') {
$(curSrc).attr("src", "../images/lightred.jpg");
}
}, 2000);
});
});

curSrc is your source attribute, yet you are trying to wrap it in jQuery, that won't make it an object. You'll have to target #red again and then set the source:
if (curSrc === '../images/lightred.jpg') {
$("#red").attr("src", "../images/Darkred.jpg");
}
if (curSrc === '../images/Darkred.jpg') {
$("#red").attr("src", "../images/lightred.jpg");
}

It seems the question might be how to make the button blink. This can be done with the css background-color property. CSS is a better fit, assuming lightRed and darkRed are solid colors. If the images are required you can use the background-image property.
<input type="button" class="search lightRed" value="Search"/>
<style>
.lightRed { background-color: lightcoral }
.darkRed { background-color: darkRed }
</style>
<script>
$(document).ready(function(){
$(".search").click(function(){
setInterval(function(){
var isLightRed = $(".search").hasClass("lightRed");
if (isLightRed) {
$(".search").removeClass("lightRed").addClass("darkRed");
} else {
$(".search").removeClass("darkRed").addClass("lightRed");
}
},2000);
});
});
</script>

Button hiding not functioning properly

HTML Code:
<div id="slick-slidetoggle">wxyz</div>
<div id="slickbox" >abcd</div>​
JavaScript:
var hoverVariable=false;
var hoverVariable2=false;
$('#slickbox').hide();
$('#slick-slidetoggle').mouseover(function() {
hoverVariable2=true;
$('#slickbox').slideToggle(600);
return false;
})
$('#slick-slidetoggle').mouseleave(function() {
hoverVariable2=false;
setTimeout(function (){
if(!hoverVariable && !hoverVariable2){
$('#slickbox').slideToggle(600);
return false;}
}, 1000);
})
$('#slickbox').mouseleave(function() {
hoverVariable=false;
setTimeout(function (){
if(!hoverVariable && !hoverVariable2){
$('#slickbox').slideToggle(600);
return false;}
return false;
}, 1000);
})
$('#slickbox').mouseover(function() {
hoverVariable2=false;
hoverVariable=true;
})​
CSS Code:
#slickbox {
background: black;
width:100px;
height: 135px;
display: none;
cursor:pointer;
color:white;
}
#slick-slidetoggle{
background: yellow;
width:100px;
height: 135px;
cursor:pointer;
color:black;
}
​
Now the desired behaviour is that when mouse is slide over yellow div("wxyz") black div("abcd") should slide down and if mouse is moved out of yellow without moving on to black div, the black div should hide after two seconds.
This is happening. If mouse is moved over black div immediately after moving out of yellow div the black div should not hide as long as the mouse is on the black div. This is also happening.
Next steps are bit difficult to explain but I'll try, when mouse is moved over yellow div and black div comes out then mouse is moved over black div and within two seconds if it moved out of it(black div) then the whole animation goes haywire. Its behaviour is reversed. But if the mouse is kept on black div for more than two seconds and then it is moved out then the whole script runs fine.
This is the link to explain better. http://jsfiddle.net/HAQyK/381/

Try replacing slideToggle() with the appropriate slideUp() and slideDown() calls. http://jsfiddle.net/tppiotrowski/HAQyK/386/
var hoverVariable = false;
var hoverVariable2 = false;
$('#slickbox').hide();
$('#slick-slidetoggle').mouseover(function() {
hoverVariable2 = true;
$('#slickbox').slideDown(600);
return false;
})
$('#slick-slidetoggle').mouseleave(function() {
hoverVariable2 = false;
setTimeout(function() {
if (!hoverVariable && !hoverVariable2) {
$('#slickbox').slideUp(600);
return false;
}
}, 1000);
})
$('#slickbox').mouseleave(function() {
hoverVariable = false;
setTimeout(function() {
if (!hoverVariable && !hoverVariable2) {
$('#slickbox').slideUp(600);
return false;
}
return false;
}, 1000);
})
$('#slickbox').mouseover(function() {
hoverVariable2 = false;
hoverVariable = true;
})​

I re-coded a solution. Checkout the fiddle here
var hideB;
var $black = $('#slickbox');
var $yellow = $('#slick-slidetoggle');
function showBlack() {
if( hideB ) window.clearTimeout( hideB );
$black.stop( true, true );
$black.slideDown(600);
}
function hideBlack() {
hideB = setTimeout( function( ) {
$black.stop( true, true );
$black.slideUp( 600 ); }
, 1000 );
}
$black.hide();
$yellow.mouseenter(function() {
showBlack();
})
$yellow.mouseleave(function() {
hideBlack();
});
$black.mouseleave( function( ) {
hideBlack();
});
$black.mouseenter( function( ) {
showBlack();
});

Your problem seems to be that the slideToggle in firing twice in quick succession because of your duplicate timeout functions. The cleanest way to deal with timeouts or intervals is to store them in a variable to give you the control of removing them when not needed:
// Defined in global scope
var timer;
$('#slick-slidetoggle').mouseleave(function() {
hoverVariable2=false;
// Timer set as function
timer = setTimeout(function (){
if(!hoverVariable && !hoverVariable2){
$('#slickbox').slideToggle(600);
// Timer no longer need and so cleared
clearTimeout(timer);
return false;}
}, 1000);
});
EDIT: Neglected to add the slideUp/slideDown instead of Toggle as per the correct answer above. See the updated jsFiddle which is now correct: http://jsfiddle.net/HAQyK/390/
Another way you could approach your script is to use jQuerys delay funciton and the stop(); method for animation. Wrap the divs in a container and you've got a much simpler block of code:
$('#slick-container').mouseenter(function() {
$('#slickbox').stop().slideDown(600);
}).mouseleave(function(){
$('#slickbox').stop().delay(1000).slideUp(600);
});
Check it out here: http://jsfiddle.net/HAQyK/387/