NO JAVASCRIPT ENABLED DETECTION

by bizamajig

HTML

<div id="content"></div>
<div id="nojs" class="nojs_init"><noscript>JavaScript is <span style="font-weight:bold;">disabled</span>.</noscript></div>

CSS

.nojs_init { 
position: relative;
animation:nojs-animation 0.2s step-end;
-moz-animation:nojs-animation 0.2s step-end; /* Firefox */
-webkit-animation:nojs-animation 0.2s step-end; /* Safari and Chrome */
-o-animation:nojs-animation 0.2s step-end; /* Opera */
}

@keyframes nojs-animation
{
from {visibility:hidden;opacity:0;}
to {visibility:visible;opacity:1;}
}

@-moz-keyframes nojs-animation /* Firefox */
{
from {visibility:hidden;opacity:0;}
to {visibility:visible;opacity:1;}
}

@-webkit-keyframes nojs-animation /* Safari and Chrome */
{
from {visibility:hidden;opacity:0;}
to {visibility:visible;opacity:1;}
}

@-o-keyframes nojs-animation /* Opera */
{
from {visibility:hidden;opacity:0;}
to {visibility:visible;opacity:1;}
}

JavaScript

document.getElementById("content").innerHTML = 'JavaScript is <span style="font-weight:bold;">enabled</span>. Try disabling JavaScript now.';

var elm = document.getElementById("nojs"),
	animation = false,
    animationstring = 'animation',
    keyframeprefix = '',
    domPrefixes = 'Webkit Moz O ms Khtml'.split(' '),
    pfx  = '';
 
if( elm.style.animationName ) { animation = true; }    
 
if( animation === false ) {
  for( var i = 0; i < domPrefixes.length; i++ ) {
    if( elm.style[ domPrefixes[i] + 'AnimationName' ] !== undefined ) {
      pfx = domPrefixes[ i ];
      animationstring = pfx + 'Animation';
      keyframeprefix = '-' + pfx.toLowerCase() + '-';
      animation = true;
      break;
    }
  }
}

function jsdetect() {
	var elm = document.getElementById("nojs");
	var newone = elm.cloneNode(true);
	elm.parentNode.replaceChild(newone, elm);
}

if (animation) {
	elm.innerHTML = 'JavaScript is <span style="font-weight:bold;">disabled</span>.';
	setInterval(jsdetect, 0);
}