Modernizr

apng.js

// This test is ascynchronous. Watch out.

(function(){

  var datauri = new Image,
  ctx = document.createElement("canvas").getContext("2d");

  datauri.onerror = function() {
    Modernizr.addTest('apng', function () { return false; });
  };

  datauri.onload = function() {
    ctx.drawImage(datauri, 0, 0);
    var apng_supported = ctx.getImageData(0, 0, 1, 1).data[3] === 0;
    Modernizr.addTest('apng', function () { return apng_supported; });
  };

  datauri.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAACGFjVEwAAAABAAAAAcMq2TYAAAANSURBVAiZY2BgYPgPAAEEAQB9ssjfAAAAGmZjVEwAAAAAAAAAAQAAAAEAAAAAAAAAAAD6A+gBAbNU+2sAAAARZmRBVAAAAAEImWNgYGBgAAAABQAB6MzFdgAAAABJRU5ErkJggg==";
  // frame 1 (skipped on apng-supporting browsers): [0, 0, 0, 255]
  // frame 2: [0, 0, 0, 0]

})();

backgroundclip.js

Modernizr.addTest('backgroundclip', function(){
  var div = document.createElement('div');
  if ('backgroundClip' in div.style){
    div.style.backgroundClip = 'text';
    return div.style.backgroundClip == 'text'
  }
  'Webkit Moz O ms Khtml'.replace(/([A-Za-z]*)/g,function(val){ 
    if (val+'BackgroundClip' in div.style) {
      div.style[val+'BackgroundClip'] = 'text';
      return div.style[val+'BackgroundClip'] == 'text'
    }
  });
  return false;
});

cssscrollbar.js

// Works only with Modernizr 1.8pre+

Modernizr.addTest('cssscrollbar', function() {

		// Tested Element
	var test = document.createElement('div'),
		
		// Fake body
		fake = false,
		root = document.body || (function () {
			fake = true;
			return document.documentElement.appendChild(document.createElement('body'));
		}()),
		
		property = 'scrollbar{width:0px;}';
	
	// Force scrollbar
	test.id = '__sb';
	test.style.overflow = 'scroll';
	test.style.width = '40px';
	
	// Apply scrollbar style for all vendors
	test.innerHTML = '&shy;<style>#'+Modernizr._prefixes.join(property+' #__sb::').split('#').slice(1).join('#')+property+'</style>';
	
	root.appendChild(test);
	
	// If css scrollbar is supported, than the scrollWidth should not be impacted
	var ret = test.scrollWidth == 40;
	
	// Cleaning
	document.body.removeChild(test);
	if (fake) {
		document.documentElement.removeChild(root);
	}
	return ret;
});

dataset.js

Modernizr.addTest('dataset', function() {
  var n = document.createElement("div");
  n.setAttribute("data-a-b", "c");
  return !!(n.dataset && n.dataset.aB == "c");
}

fontsmoothing.js

Modernizr.addTest('fontsmoothing', function(){
      // IE has screen.fontSmoothingEnabled - sweet!
      if (screen.fontSmoothingEnabled !== undefined) {
         return screen.fontSmoothingEnabled;
      } else {
         try {
            // Create a 35x35 Canvas block.
            var canvasNode = document.createElement('canvas'), ctx, j, i,
              imageData, alpha;
            canvasNode.width = '35';
            canvasNode.height = '35';

            // We must put this node into the body, otherwise
            // Safari Windows does not report correctly.
            canvasNode.style.display = 'none';
            document.body.appendChild(canvasNode);
            ctx = canvasNode.getContext('2d');

            // draw a black letter 'O', 32px Arial.
            ctx.textBaseline = 'top';
            ctx.font = '32px Arial';
            ctx.fillStyle = 'black';
            ctx.strokeStyle = 'black';

            ctx.fillText('O', 0, 0);

            // start at (8,1) and search the canvas from left to right,
            // top to bottom to see if we can find a non-black pixel.  If
            // so we return true.
            for (j = 8; j <= 32; j++) {
               for (i = 1; i <= 32; i++) {

                  imageData = ctx.getImageData(i, j, 1, 1).data;
                  alpha = imageData[3];

                  if (alpha != 255 && alpha != 0) {
                     return true; // font-smoothing must be on.
                  }
               }

            }

            // didn't find any non-black pixels - return false.
            return false;
         }
         catch (ex) {
            // Something went wrong (for example, Opera cannot use the
            // canvas fillText() method.  Return null (unknown).
            return null;
         }
      }
   }

ie8compat.js

Modernizr.addTest('ie8compat',function(){
  return !window.addEventListener && document.documentMode && document.documentMode == 7;
});

positionfixed.js

// feature test for position fixed.

Modernizr.addTest('positionfixed', function () {
    var test    = document.createElement('div'),
        control = test.cloneNode(false),
        fake = false,
        root = document.body || (function () {
            fake = true;
            return document.documentElement.appendChild(document.createElement('body'));
        }());

    var oldCssText = root.style.cssText;
    root.style.cssText = 'padding:0;margin:0';
    test.style.cssText = 'position:fixed;top:42px'; 
    root.appendChild(test);
    root.appendChild(control);
    
    var ret = test.offsetTop !== control.offsetTop;

    root.removeChild(test);
    root.removeChild(control);
    root.style.cssText = oldCssText;
    
    if (fake) {
        document.documentElement.removeChild(root);
    }

    return ret;
});

table_display.js

(function() {
	var displayTests = ["table", "table-caption", "table-cell", 
	"table-column", "table-column-group", "table-footer-group", 
	"table-header-group", "table-row", "table-row-group"];
	
	var rules = document.createElement("div").style;

	for (var c=0; c<displayTests.length; c++) {
		var testValue = displayTests[c];
		Modernizr.addTest("display" + testValue, function() {
			try {
				rules.display = testValue;
				return rules.display == testValue;
			} catch (e) {
				return false;
			}
		})
	}
}());

userdata.js

//test if IE userdata supported

Modernizr.addTest('userdata', function(){
  return !!(document.createElement('div')).addBehavior;
});

volumecontrol.js

// Apple decided to not give control of <audio> & <video> volume...

Modernizr.addTest('volumecontrol', function() {
        // Tested Element
	var test = document.createElement('audio');
	test.volume = 0.5;
	return Modernizr.audio && test.volume === 0.5;
});