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easing speed of blink for text in a jackpot game

I am making a jackpot game with a selector very similar to this one
I have absolutely no idea where to start. My first thought was to use an array of randomly selected numbers sent from the server side to avoid cheating and animate those with jquery or css.
Then i thought about useing just jquery since i know it better and having the blink interval be a recursive fucnction that returns the values for easing speed i want. (the values would be pretty much exactly like in the video, no more than 3-4 seconds).
$('.blink').blink(); // default is 500ms blink interval.
$('.blink').blink(100); // causes a 100ms blink interval.
But now I am at a loss for where to get started since this has to be mobile friendly. What would you do?
UPDATE
$( document ).ready(function() {
var time = 0;
var diff = 50;
var minTime = 0;
var maxTime = 7000;
function easeInOutExpo(t, b, c, d) {
t /= d;
return c*t*t*t + b;
};
$("#clickme").click(function() {
for (var i = 0, len = diff; i <= len; i++) {
(function(s) {
setTimeout(function() {
$('#book').html("Page " + s + " turned");
}, time);
})(i); //<--------------i have no clue what this does------------
time = easeInOutExpo(i, minTime, maxTime, diff);
}
});
});//document ready
I've gotten the basic mechanic down, but when you click on it a second time instead of 50 it goes to 0. this is not good behavior as I am going to use these numbers to iterate through a randomly generated array.
Can anyone explain this behaviour? I've included a JS fiddle here. Thank you!

You can use simple css animation.
#keyframes blink {
0% { background-color:red; }
10% { background-color:purple; }
20% { background-color:gray; }
30% { background-color:green; }
40% { background-color:white; }
50% { background-color:cyan; }
65% { background-color:yellow; }
100% { background-color:black }
}
.Blink{
animation: blink 2s 1 ease-out;
background-color:black;
height:100px;
width:100px;
}
<div class="Blink">

How can I create an efficient infinitely looping waving text animation?

This is the effect I am trying to create (JSFiddle):
$('.header h1 span').each(function() { // each letter is contained inside a <span> element
var that = $(this);
setTimeout(function() {
that.animate({
top: "-10px"
}, animateTime / 2)
.animate({
top: "10px"
}, animateTime / 2);
}, that.index() * 100);
});
Result:
It appears to be successful. However, I ran into the problem of it looking like this after switching tabs, then coming back:
In the fiddle above, I've tried to "fix" this by making the animation stop when the tab is unfocused. It's better than when I WASN'T checking for tab unfocusing, but it still has problems. This is the code I'm using to do that:
var running = true;
document.addEventListener('visibilitychange', function(){
console.log("Running:" + running);
running = !document.hidden;
if(!running) clearQueues();
})
If the user spends less than a couple seconds unfocused from the tab, the animation looks like the second GIF again, and I don't see a way to avoid that. I've tried using requestAnimationFrame() but I can't figure out how to make it behave correctly.
So, my question is: how do I prevent the animation from being affected by the tab being unfocused?
Bonus points (figuratively) if you can help me make it more efficient on mobile, too.

I'm not sure if this solves the stuttering for you or not. This strategy is similar in concept to what you are doing, but uses CSS animation rather than js.
(function(){
var el = document.querySelectorAll(".wavey")[0];
var oldText = el.innerText
var newHtml = "";
for (var i in el.innerText) { newHtml += ("<span style='animation-delay: " + i/10 + "s;'>" + oldText[i] + "</span>"); }
el.innerHTML = newHtml;
})();
#keyframes wave {
from { transform: translateY(0); }
to { transform: translateY(-1em); }
}
h1.wavey { margin-top: 2em; }
h1.wavey span {
display: inline-block;
animation-duration: 1s;
animation-name: wave;
animation-iteration-count: infinite;
animation-direction: alternate;
animation-timing-function: ease-in-out;
}
<h1 class="wavey">Hello World</h1>

Flashing text on value change [duplicate]

I'm brand new to jQuery and have some experience using Prototype. In Prototype, there is a method to "flash" an element — ie. briefly highlight it in another color and have it fade back to normal so that the user's eye is drawn to it. Is there such a method in jQuery? I see fadeIn, fadeOut, and animate, but I don't see anything like "flash". Perhaps one of these three can be used with appropriate inputs?

My way is .fadein, .fadeout .fadein, .fadeout ......
$("#someElement").fadeOut(100).fadeIn(100).fadeOut(100).fadeIn(100);
function go1() { $("#demo1").fadeOut(100).fadeIn(100).fadeOut(100).fadeIn(100)}
function go2() { $('#demo2').delay(100).fadeOut().fadeIn('slow') }
#demo1,
#demo2 {
text-align: center;
font-family: Helvetica;
background: IndianRed;
height: 50px;
line-height: 50px;
width: 150px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button onclick="go1()">Click Me</button>
<div id='demo1'>My Element</div>
<br>
<button onclick="go2()">Click Me</button> (from comment)
<div id='demo2'>My Element</div>

You can use the jQuery Color plugin.
For example, to draw attention to all the divs on your page, you could use the following code:
$("div").stop().css("background-color", "#FFFF9C")
.animate({ backgroundColor: "#FFFFFF"}, 1500);
Edit - New and improved
The following uses the same technique as above, but it has the added benefits of:
parameterized highlight color and duration
retaining original background color, instead of assuming that it is white
being an extension of jQuery, so you can use it on any object
Extend the jQuery Object:
var notLocked = true;
$.fn.animateHighlight = function(highlightColor, duration) {
var highlightBg = highlightColor || "#FFFF9C";
var animateMs = duration || 1500;
var originalBg = this.css("backgroundColor");
if (notLocked) {
notLocked = false;
this.stop().css("background-color", highlightBg)
.animate({backgroundColor: originalBg}, animateMs);
setTimeout( function() { notLocked = true; }, animateMs);
}
};
Usage example:
$("div").animateHighlight("#dd0000", 1000);

You can use css3 animations to flash an element
.flash {
-moz-animation: flash 1s ease-out;
-moz-animation-iteration-count: 1;
-webkit-animation: flash 1s ease-out;
-webkit-animation-iteration-count: 1;
-ms-animation: flash 1s ease-out;
-ms-animation-iteration-count: 1;
}
#keyframes flash {
0% { background-color: transparent; }
50% { background-color: #fbf8b2; }
100% { background-color: transparent; }
}
#-webkit-keyframes flash {
0% { background-color: transparent; }
50% { background-color: #fbf8b2; }
100% { background-color: transparent; }
}
#-moz-keyframes flash {
0% { background-color: transparent; }
50% { background-color: #fbf8b2; }
100% { background-color: transparent; }
}
#-ms-keyframes flash {
0% { background-color: transparent; }
50% { background-color: #fbf8b2; }
100% { background-color: transparent; }
}
And you jQuery to add the class
jQuery(selector).addClass("flash");

After 5 years... (And no additional plugin needed)
This one "pulses" it to the color you want (e.g. white) by putting a div background color behind it, and then fading the object out and in again.
HTML object (e.g. button):
<div style="background: #fff;">
<input type="submit" class="element" value="Whatever" />
</div>
jQuery (vanilla, no other plugins):
$('.element').fadeTo(100, 0.3, function() { $(this).fadeTo(500, 1.0); });
element - class name
first number in fadeTo() - milliseconds for the transition
second number in fadeTo() - opacity of the object after fade/unfade
You may check this out in the lower right corner of this webpage: https://single.majlovesreg.one/v1/
Edit (willsteel) no duplicated selector by using $(this) and tweaked values to acutally perform a flash (as the OP requested).

You could use the highlight effect in jQuery UI to achieve the same, I guess.

If you're using jQueryUI, there is pulsate function in UI/Effects
$("div").click(function () {
$(this).effect("pulsate", { times:3 }, 2000);
});
http://docs.jquery.com/UI/Effects/Pulsate

$('#district').css({opacity: 0});
$('#district').animate({opacity: 1}, 700 );

Pure jQuery solution.
(no jquery-ui/animate/color needed.)
If all you want is that yellow "flash" effect without loading jquery color:
var flash = function(elements) {
var opacity = 100;
var color = "255, 255, 20" // has to be in this format since we use rgba
var interval = setInterval(function() {
opacity -= 3;
if (opacity <= 0) clearInterval(interval);
$(elements).css({background: "rgba("+color+", "+opacity/100+")"});
}, 30)
};
Above script simply does 1s yellow fadeout, perfect for letting the user know the element was was updated or something similar.
Usage:
flash($('#your-element'))

You could use this plugin (put it in a js file and use it via script-tag)
http://plugins.jquery.com/project/color
And then use something like this:
jQuery.fn.flash = function( color, duration )
{
var current = this.css( 'color' );
this.animate( { color: 'rgb(' + color + ')' }, duration / 2 );
this.animate( { color: current }, duration / 2 );
}
This adds a 'flash' method to all jQuery objects:
$( '#importantElement' ).flash( '255,0,0', 1000 );

You can extend Desheng Li's method further by allowing an iterations count to do multiple flashes like so:
// Extend jquery with flashing for elements
$.fn.flash = function(duration, iterations) {
duration = duration || 1000; // Default to 1 second
iterations = iterations || 1; // Default to 1 iteration
var iterationDuration = Math.floor(duration / iterations);
for (var i = 0; i < iterations; i++) {
this.fadeOut(iterationDuration).fadeIn(iterationDuration);
}
return this;
}
Then you can call the method with a time and number of flashes:
$("#someElementId").flash(1000, 4); // Flash 4 times over a period of 1 second

How about a really simple answer?
$('selector').fadeTo('fast',0).fadeTo('fast',1).fadeTo('fast',0).fadeTo('fast',1)
Blinks twice...that's all folks!

I can't believe this isn't on this question yet. All you gotta do:
("#someElement").show('highlight',{color: '#C8FB5E'},'fast');
This does exactly what you want it to do, is super easy, works for both show() and hide() methods.

This may be a more up-to-date answer, and is shorter, as things have been consolidated somewhat since this post. Requires jquery-ui-effect-highlight.
$("div").click(function () {
$(this).effect("highlight", {}, 3000);
});
http://docs.jquery.com/UI/Effects/Highlight

function pulse() {
$('.blink').fadeIn(300).fadeOut(500);
}
setInterval(pulse, 1000);

I was looking for a solution to this problem but without relying on jQuery UI.
This is what I came up with and it works for me (no plugins, just Javascript and jQuery);
-- Heres the working fiddle -- http://jsfiddle.net/CriddleCraddle/yYcaY/2/
Set the current CSS parameter in your CSS file as normal css, and create a new class that just handles the parameter to change i.e. background-color, and set it to '!important' to override the default behavior. like this...
.button_flash {
background-color: #8DABFF !important;
}//This is the color to change to.
Then just use the function below and pass in the DOM element as a string, an integer for the number of times you would want the flash to occur, the class you want to change to, and an integer for delay.
Note: If you pass in an even number for the 'times' variable, you will end up with the class you started with, and if you pass an odd number you will end up with the toggled class. Both are useful for different things. I use the 'i' to change the delay time, or they would all fire at the same time and the effect would be lost.
function flashIt(element, times, klass, delay){
for (var i=0; i < times; i++){
setTimeout(function(){
$(element).toggleClass(klass);
}, delay + (300 * i));
};
};
//Then run the following code with either another delay to delay the original start, or
// without another delay. I have provided both options below.
//without a start delay just call
flashIt('.info_status button', 10, 'button_flash', 500)
//with a start delay just call
setTimeout(function(){
flashIt('.info_status button', 10, 'button_flash', 500)
}, 4700);
// Just change the 4700 above to your liking for the start delay. In this case,
//I need about five seconds before the flash started.

Would a pulse effect(offline) JQuery plugin be appropriate for what you are looking for ?
You can add a duration for limiting the pulse effect in time.
As mentioned by J-P in the comments, there is now his updated pulse plugin.
See his GitHub repo. And here is a demo.

Found this many moons later but if anyone cares, it seems like this is a nice way to get something to flash permanently:
$( "#someDiv" ).hide();
setInterval(function(){
$( "#someDiv" ).fadeIn(1000).fadeOut(1000);
},0)

The following codes work for me. Define two fade-in and fade-out functions and put them in each other's callback.
var fIn = function() { $(this).fadeIn(300, fOut); };
var fOut = function() { $(this).fadeOut(300, fIn); };
$('#element').fadeOut(300, fIn);
The following controls the times of flashes:
var count = 3;
var fIn = function() { $(this).fadeIn(300, fOut); };
var fOut = function() { if (--count > 0) $(this).fadeOut(300, fIn); };
$('#element').fadeOut(300, fIn);

If including a library is overkill here is a solution that is guaranteed to work.
$('div').click(function() {
$(this).css('background-color','#FFFFCC');
setTimeout(function() { $(this).fadeOut('slow').fadeIn('slow'); } , 1000);
setTimeout(function() { $(this).css('background-color','#FFFFFF'); } , 1000);
});
Setup event trigger
Set the background color of block element
Inside setTimeout use fadeOut and fadeIn to create a little animation effect.
Inside second setTimeout reset default background color
Tested in a few browsers and it works nicely.

Like fadein / fadeout you could use animate css / delay
$(this).stop(true, true).animate({opacity: 0.1}, 100).delay(100).animate({opacity: 1}, 100).animate({opacity: 0.1}, 100).delay(100).animate({opacity: 1}, 100);
Simple and flexible

$("#someElement").fadeTo(3000, 0.3 ).fadeTo(3000, 1).fadeTo(3000, 0.3 ).fadeTo(3000, 1);
3000 is 3 seconds
From opacity 1 it is faded to 0.3, then to 1 and so on.
You can stack more of these.
Only jQuery is needed. :)

There is a workaround for the animate background bug. This gist includes an example of a simple highlight method and its use.
/* BEGIN jquery color */
(function(jQuery){jQuery.each(['backgroundColor','borderBottomColor','borderLeftColor','borderRightColor','borderTopColor','color','outlineColor'],function(i,attr){jQuery.fx.step[attr]=function(fx){if(!fx.colorInit){fx.start=getColor(fx.elem,attr);fx.end=getRGB(fx.end);fx.colorInit=true;}
fx.elem.style[attr]="rgb("+[Math.max(Math.min(parseInt((fx.pos*(fx.end[0]-fx.start[0]))+fx.start[0]),255),0),Math.max(Math.min(parseInt((fx.pos*(fx.end[1]-fx.start[1]))+fx.start[1]),255),0),Math.max(Math.min(parseInt((fx.pos*(fx.end[2]-fx.start[2]))+fx.start[2]),255),0)].join(",")+")";}});function getRGB(color){var result;if(color&&color.constructor==Array&&color.length==3)
return color;if(result=/rgb\(\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*,\s*([0-9]{1,3})\s*\)/.exec(color))
return[parseInt(result[1]),parseInt(result[2]),parseInt(result[3])];if(result=/rgb\(\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*,\s*([0-9]+(?:\.[0-9]+)?)\%\s*\)/.exec(color))
return[parseFloat(result[1])*2.55,parseFloat(result[2])*2.55,parseFloat(result[3])*2.55];if(result=/#([a-fA-F0-9]{2})([a-fA-F0-9]{2})([a-fA-F0-9]{2})/.exec(color))
return[parseInt(result[1],16),parseInt(result[2],16),parseInt(result[3],16)];if(result=/#([a-fA-F0-9])([a-fA-F0-9])([a-fA-F0-9])/.exec(color))
return[parseInt(result[1]+result[1],16),parseInt(result[2]+result[2],16),parseInt(result[3]+result[3],16)];if(result=/rgba\(0, 0, 0, 0\)/.exec(color))
return colors['transparent'];return colors[jQuery.trim(color).toLowerCase()];}
function getColor(elem,attr){var color;do{color=jQuery.curCSS(elem,attr);if(color!=''&&color!='transparent'||jQuery.nodeName(elem,"body"))
break;attr="backgroundColor";}while(elem=elem.parentNode);return getRGB(color);};var colors={aqua:[0,255,255],azure:[240,255,255],beige:[245,245,220],black:[0,0,0],blue:[0,0,255],brown:[165,42,42],cyan:[0,255,255],darkblue:[0,0,139],darkcyan:[0,139,139],darkgrey:[169,169,169],darkgreen:[0,100,0],darkkhaki:[189,183,107],darkmagenta:[139,0,139],darkolivegreen:[85,107,47],darkorange:[255,140,0],darkorchid:[153,50,204],darkred:[139,0,0],darksalmon:[233,150,122],darkviolet:[148,0,211],fuchsia:[255,0,255],gold:[255,215,0],green:[0,128,0],indigo:[75,0,130],khaki:[240,230,140],lightblue:[173,216,230],lightcyan:[224,255,255],lightgreen:[144,238,144],lightgrey:[211,211,211],lightpink:[255,182,193],lightyellow:[255,255,224],lime:[0,255,0],magenta:[255,0,255],maroon:[128,0,0],navy:[0,0,128],olive:[128,128,0],orange:[255,165,0],pink:[255,192,203],purple:[128,0,128],violet:[128,0,128],red:[255,0,0],silver:[192,192,192],white:[255,255,255],yellow:[255,255,0],transparent:[255,255,255]};})(jQuery);
/* END jquery color */
/* BEGIN highlight */
jQuery(function() {
$.fn.highlight = function(options) {
options = (options) ? options : {start_color:"#ff0",end_color:"#fff",delay:1500};
$(this).each(function() {
$(this).stop().css({"background-color":options.start_color}).animate({"background-color":options.end_color},options.delay);
});
}
});
/* END highlight */
/* BEGIN highlight example */
$(".some-elements").highlight();
/* END highlight example */
https://gist.github.com/1068231

Unfortunately the top answer requires JQuery UI. http://api.jquery.com/animate/
Here is a vanilla JQuery solution
http://jsfiddle.net/EfKBg/
JS
var flash = "<div class='flash'></div>";
$(".hello").prepend(flash);
$('.flash').show().fadeOut('slow');
CSS
.flash {
background-color: yellow;
display: none;
position: absolute;
width: 100%;
height: 100%;
}
HTML
<div class="hello">Hello World!</div>

Here's a slightly improved version of colbeerhey's solution. I added a return statement so that, in true jQuery form, we chain events after calling the animation. I've also added the arguments to clear the queue and jump to the end of an animation.
// Adds a highlight effect
$.fn.animateHighlight = function(highlightColor, duration) {
var highlightBg = highlightColor || "#FFFF9C";
var animateMs = duration || 1500;
this.stop(true,true);
var originalBg = this.css("backgroundColor");
return this.css("background-color", highlightBg).animate({backgroundColor: originalBg}, animateMs);
};

This one will pulsate an element's background color until a mouseover event is triggered
$.fn.pulseNotify = function(color, duration) {
var This = $(this);
console.log(This);
var pulseColor = color || "#337";
var pulseTime = duration || 3000;
var origBg = This.css("background-color");
var stop = false;
This.bind('mouseover.flashPulse', function() {
stop = true;
This.stop();
This.unbind('mouseover.flashPulse');
This.css('background-color', origBg);
})
function loop() {
console.log(This);
if( !stop ) {
This.animate({backgroundColor: pulseColor}, pulseTime/3, function(){
This.animate({backgroundColor: origBg}, (pulseTime/3)*2, 'easeInCirc', loop);
});
}
}
loop();
return This;
}

Put this together from all of the above - an easy solution for flashing an element and return to the original bgcolour...
$.fn.flash = function (highlightColor, duration, iterations) {
var highlightBg = highlightColor || "#FFFF9C";
var animateMs = duration || 1500;
var originalBg = this.css('backgroundColor');
var flashString = 'this';
for (var i = 0; i < iterations; i++) {
flashString = flashString + '.animate({ backgroundColor: highlightBg }, animateMs).animate({ backgroundColor: originalBg }, animateMs)';
}
eval(flashString);
}
Use like this:
$('<some element>').flash('#ffffc0', 1000, 3);
Hope this helps!

Here's a solution that uses a mix of jQuery and CSS3 animations.
http://jsfiddle.net/padfv0u9/2/
Essentially you start by changing the color to your "flash" color, and then use a CSS3 animation to let the color fade out. You need to change the transition duration in order for the initial "flash" to be faster than the fade.
$(element).removeClass("transition-duration-medium");
$(element).addClass("transition-duration-instant");
$(element).addClass("ko-flash");
setTimeout(function () {
$(element).removeClass("transition-duration-instant");
$(element).addClass("transition-duration-medium");
$(element).removeClass("ko-flash");
}, 500);
Where the CSS classes are as follows.
.ko-flash {
background-color: yellow;
}
.transition-duration-instant {
-webkit-transition-duration: 0s;
-moz-transition-duration: 0s;
-o-transition-duration: 0s;
transition-duration: 0s;
}
.transition-duration-medium {
-webkit-transition-duration: 1s;
-moz-transition-duration: 1s;
-o-transition-duration: 1s;
transition-duration: 1s;
}

just give elem.fadeOut(10).fadeIn(10);

This is generic enough that you can write whatever code you like to animate. You can even decrease the delay from 300ms to 33ms and fade colors, etc.
// Flash linked to hash.
var hash = location.hash.substr(1);
if (hash) {
hash = $("#" + hash);
var color = hash.css("color"), count = 1;
function hashFade () {
if (++count < 7) setTimeout(hashFade, 300);
hash.css("color", count % 2 ? color : "red");
}
hashFade();
}

you can use jquery Pulsate plugin to force to focus the attention on any html element with control over speed and repeatation and color.
JQuery.pulsate() * with Demos
sample initializer:
$(".pulse4").pulsate({speed:2500})
$(".CommandBox button:visible").pulsate({ color: "#f00", speed: 200, reach: 85, repeat: 15 })

Animated PNG background with Javascript, but without loop?

I need help with an animated PNG in Javascript.
I found how to animate a PNG background with Javascript here on Stack Overflow. But my problem is that I only need the animation onmouseover and onmouseout. And the animation should play only once, not in a loop, so when the user moves the mouse over a div the the animation in the background should play once and stop at the last frame, but when the user goes off the div, a reverse animation should play once and stop at the last (first) frame. The script I found here is:
The style:
#anim {
width: 240px; height: 60px;
background-image: url(animleft.png);
background-repeat: no-repeat;
}
The HTML:
<div id="anim"></div>
Javascript:
var scrollUp = (function () {
var timerId; // stored timer in case you want to use clearInterval later
return function (height, times, element) {
var i = 0; // a simple counter
timerId = setInterval(function () {
if (i > times) // if the last frame is reached, set counter to zero
i = 0;
element.style.backgroundPosition = "0px -" + i * height + 'px'; //scroll up
i++;
}, 100); // every 100 milliseconds
};
})();
// start animation:
scrollUp(14, 42, document.getElementById('anim'))
I hope anyone can help me, Thank you

To stop the animation after the first set of frames you do want to change the if condition to not reset the counter to zero but instead to clear the interval and stop it from reoccuring.
To only let it play when you enter an element you can attach the animation function as an event listener and play the whole thing in reverse with another function that you plug into your onmouseout event.

Depending on your target browser and since your question is fairly vague I can recommend two alternatives to you:
Use jQuery animate (all browsers, include ref to jquery)
//Animate to x,y where x and y are final positions
$('#anim').mouseenter(function(e) {
$(this).animate({background-position: x + 'px ' + y + 'px'}, 4200);
})
//Do same for mouseleave
Use a css3 animation (using -webkit browser here)
<style>
#-webkit-keyframes resize {
100% {
height: 123px;
}
}
#anim:hover {
-webkit-animation-name: resize;
-webkit-animation-duration: 4s;
}
I would choose option 2 if you are doing mobile development or can choose only css3 capable browsers.

Creating a loading screen in HTML5

I am having some issues finding a decent tutorial for generating a loading style screen with regards to HTML5. To be quite honest I'm not sure exactly where to begin...
My project is essentially a simple HTML5 game, where I'll be loading in various sprite sheets and tilesets. They'll be reasonably small, but I'd like to show a little loading spinner instead of a blank screen while all the resources are loaded.
Much appreciated if somebody could point me in the right direction, be it decent links or code samples to get me going...my Google-fu is lacking today!
For clarification, I need to figure out how to load the resources themselves, as opposed to finding a spinner. For instance, how to calculate that X% has loaded.
Edit 2
Silly me, I can just check for <variable>.image.complete. Voted to close.

This website is excellent for animated loading gifs: http://ajaxload.info/. An overlay can be used to display the image and also prevent interaction with the page while it is loading. You can use a div, position it above everything else (z-index) and set the width and height to 100%.

An old question, but it is usefull to know that the Image object also has an onload event. It is often way better to use that than check for complete in for example a loop.
Example usage (not actually checked if working):
var numImagesLoaded = 0;
function incrementAndCheckLoading(){
numImagesLoaded++;
if(numImagesLoaded == 2){
// Do some stuff like remove loading screen or redirect to other URL
}
}
image1 = new Image();
image1.src = "image1.jpg"
image1.onload = incrementAndCheckLoading;
image2 = new Image();
image2.src = "image2.jpg"
image2.onload = incrementAndCheckLoading;

This is an excellent resource for demonstrating HTML5 CSS animation.
http://slides.html5rocks.com/#css-animation
#-webkit-keyframes pulse {
from {
opacity: 0.0;
font-size: 100%;
}
to {
opacity: 1.0;
font-size: 200%;
}
}
div {
-webkit-animation-name: pulse;
-webkit-animation-duration: 2s;
-webkit-animation-iteration-count: infinite;
-webkit-animation-timing-function: ease-in-out;
-webkit-animation-direction: alternate;
}
This demonstrates how to create a loading status bar:
http://slides.html5rocks.com/#semantic-tags-2
<progress>working...</progress>
There are plenty of other examples on those slides as well that may have what you're looking for.

You can use <progress> element in HTML5. See this page for source code and live demo.
http://purpledesign.in/blog/super-cool-loading-bar-html5/
here is the progress element...
<progress id="progressbar" value="20" max="100"></progress>
this will have the loading value starting from 20. Of course only the element wont suffice. You need to move it as the script loads. For that we need JQuery. Here is a simple JQuery script that starts the progress from 0 to 100 and does something in defined time slot.
<script>
$(document).ready(function() {
if(!Modernizr.meter){
alert('Sorry your brower does not support HTML5 progress bar');
} else {
var progressbar = $('#progressbar'),
max = progressbar.attr('max'),
time = (1000/max)*10,
value = progressbar.val();
var loading = function() {
value += 1;
addValue = progressbar.val(value);
$('.progress-value').html(value + '%');
if (value == max) {
clearInterval(animate);
//Do Something
}
if (value == 16) {
//Do something
}
if (value == 38) {
//Do something
}
if (value == 55) {
//Do something
}
if (value == 72) {
//Do something
}
if (value == 1) {
//Do something
}
if (value == 86) {
//Do something
}
};
var animate = setInterval(function() {
loading();
}, time);
};
});
</script>
Add this to your HTML file.
<div class="demo-wrapper html5-progress-bar">
<div class="progress-bar-wrapper">
<progress id="progressbar" value="0" max="100"></progress>
<span class="progress-value">0%</span>
</div>
</div>
Hope this will give you a start.

Because this question is tagged with html5 - I think we can do better than a spinner gif. A more modern alternative:
http://fgnass.github.io/spin.js/