How TO - JavaScript HTML Animations

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How TO - JavaScript HTML Animations

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Learn how to create animations using JavaScript.

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A Basic Web Page

To demonstrate how to create HTML animations with JavaScript, we can use a simple
web page.

Example

<!DOCTYPE html>
<html>
<body>

<h1>My First
JavaScript Animation</h1>

<div id ="myContainer">
<div id ="myAnimation">My
animation will go here</div>
</div>

</body>
<html>

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Styling the Elements

To make an animation possible, the animated element must be animated relative
to a "parent container".

The container element should be created with style = "position: relative".

The animation element should be created with style = "position: absolute".

Example

#myContainer
    width: 400px;
    height:
400px;
    position: relative;

background: yellow;

#myAnimation
    width: 50px;
    height:
50px;
    position: absolute;

background: red;

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The Animation Code

JavaScript animations are done by programming gradual changes in an element's
style.

The changes are called by a timer. When the timer interval is small, the
animation looks continuous.

The basic code is:

Example

var id = setInterval(frame, 5);

function frame()
    if (/*
test for finished */)
        clearInterval(id);
     else

/* code to change the element style */

Create the Animation Using JavaScript

Example

function myMove()
    var elem =
document.getElementById("myAnimation");
    var pos = 0;
    var id = setInterval(frame,
10);

function frame()
        if (pos ==
350)

clearInterval(id);
        else

pos++;

elem.style.top = pos + 'px';
            elem.style.left = pos + 'px';

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