A Pen by Rik Roots.

index.html

<div id="mystack" class="scrawlstack zero">
	<canvas id="mycanvas" class="zero"></canvas>
	<div id="page1" class="zero">
		<h1 class="center">Page loading effects</h1>
		<div class="center">
			<h2>Select effect:</h2>
			<p>
				<select id="effect">
					<option value="fog" selected>Fog</option>
					<option value="clearFromCenter">Rolling rectangle</option>
					<option value="starburst">Spinning star</option>
					<option value="roller">Chop from top</option>
					<option value="clearCircles">Clear with circles</option>
				</select>
			</p>
			<p><button id="startButton" type="button">Display effect</button></p>
		</div>
	<p>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec odio. Praesent libero. Sed cursus ante dapibus diam. Sed nisi. Nulla quis sem at nibh elementum imperdiet. Duis sagittis ipsum. Praesent mauris. Fusce nec tellus sed augue semper porta. Mauris massa. Vestibulum lacinia arcu eget nulla. Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Curabitur sodales ligula in libero. </p>

	<p>Sed dignissim lacinia nunc. Curabitur tortor. Pellentesque nibh. Aenean quam. In scelerisque sem at dolor. Maecenas mattis. Sed convallis tristique sem. Proin ut ligula vel nunc egestas porttitor. Morbi lectus risus, iaculis vel, suscipit quis, luctus non, massa. Fusce ac turpis quis ligula lacinia aliquet. Mauris ipsum. Nulla metus metus, ullamcorper vel, tincidunt sed, euismod in, nibh. Quisque volutpat condimentum velit. </p>

	<p>Class aptent taciti sociosqu ad litora torquent per conubia nostra, per inceptos himenaeos. Nam nec ante. Sed lacinia, urna non tincidunt mattis, tortor neque adipiscing diam, a cursus ipsum ante quis turpis. Nulla facilisi. Ut fringilla. Suspendisse potenti. Nunc feugiat mi a tellus consequat imperdiet. Vestibulum sapien. Proin quam. Etiam ultrices. Suspendisse in justo eu magna luctus suscipit. Sed lectus. Integer euismod lacus luctus magna. </p>

</div>
	<div id="page2" class="zero">
		<div class="center">
			<button id="returnButton" type="button">Return to main page</button>
		</div>
		<iframe id="myframe" src="about:blank"></iframe>
	</div>
</div>
<script src="http://scrawl.rikweb.org.uk/js/scrawlCore-min.js"></script>

script.js

var mycode = function(){
  //define variables
  var pad = scrawl.pad.mycanvas,
      cell = scrawl.cell[pad.base],
      stack = scrawl.stack.mystack,
      page1 = scrawl.element.page1,
      page2 = scrawl.element.page2,
      browserWidth = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth,
      browserHeight = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight,
      startButton = document.getElementById('startButton'),
      returnButton = document.getElementById('returnButton'),
      effectSelector = document.getElementById('effect'),
      getEffect, currentEffect,
      frame = document.getElementById('myframe'),
      frameSources = [
        'http://en.wikipedia.org/wiki/Cat',
        'http://en.wikipedia.org/wiki/Dog',
        'http://en.wikipedia.org/wiki/Goat',
        'http://en.wikipedia.org/wiki/Rabbit',
        'http://en.wikipedia.org/wiki/Parrot',
        'http://en.wikipedia.org/wiki/Sea_slug',
        'http://en.wikipedia.org/wiki/Orchid',
        'http://en.wikipedia.org/wiki/Rose',
        'http://en.wikipedia.org/wiki/HTML5',
        'http://en.wikipedia.org/wiki/Css',
        'http://en.wikipedia.org/wiki/Javascript'
      ],
      currentFrame,
      newFrame,
      doButtons,
      resize,
      checkE,
      myBlock, myStar, myCircles, myCirclesGroup,
      fogIn, fogOut, doFog, buildFog,
      clearFromCenterIn, clearFromCenterOut, doClearFromCenter, buildClearFromCenter,
      starburstIn, starburstOut, doStarburst, buildStarburst,
      rollerIn, rollerOut, doRoller, buildRoller,
      clearCirclesIn, clearCirclesOut, doClearCircles, buildClearCircles,
      showPad, hidePad, switchPages, clearSprites;

  //initial setup of DOM elements in stack
  stack.set({	startX: 15,		startY: 15});
  pad.set({	translateZ: 0});
  page1.set({	translateZ: 1,	visibility: true});
  page2.set({	translateZ: -1,	visibility: false});

  //functions for manipulating the display of various page sections (page1, page2, pad)
  showPad = function(){
    pad.set({	translateZ: 2});
  };
  hidePad = function(){
    pad.set({	translateZ: 0});
  };
  switchPages = function(){
    if(page1.visibility){
      page1.set({	translateZ: -1,	visibility: false});
      page2.set({	translateZ: 1,	visibility: true});
    }
    else{
      page1.set({translateZ: 1,	visibility: true});
      page2.set({translateZ: -1,	visibility: false});
    }
  };
  //determine which wikipedia page to display in the iframe
  newFrame = function(){
    currentFrame = Math.floor(Math.random() * frameSources.length);
  };

  //define sprites to be used in animations
  clearSprites = function(){
    scrawl.group[pad.base].setSpritesTo({
      visibility: false,
    });
    myCirclesGroup.setSpritesTo({
      visibility: false,
    });
  };
  myBlock = scrawl.newBlock({
    name: 'myblock',
    fillStyle: 'white',
    visibility: false,
  });
  myStar = scrawl.makeRegularShape({
    name: 'mystar',
    fillStyle: 'gold',
    method: 'fill',
    radius: 1000,
    angle: 144,
    visibility: false,
  });
  myCircles = [];
  myCirclesGroup = scrawl.newGroup({
    name: 'circles',
  });
  for(var i = 0; i < 20; i++){
    myCircles.push(scrawl.newWheel({
      radius: 200,
      group: 'circles',
      fillStyle: 'lightblue',
      visibility: false,
    }));
  }

  //event listeners
  checkE = function(e){				//common function to halt propogation of event
    if(e){
      e.preventDefault();
      e.returnValue=false;
    }
  };
  resize = function(e){				//listen and respond to browser resizing
    browserWidth = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth,
      browserHeight = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight,
      browserWidth -= 45;
    stack.set({	width: browserWidth,	height: browserHeight});
    pad.set({	width: browserWidth,	height: browserHeight});
    cell.set({	width: browserWidth,	height: browserHeight});
    page1.set({	width: browserWidth});
    page2.set({	width: browserWidth});
    frame.width = browserWidth - 10;
    frame.height = browserHeight - 50;
    checkE(e);
  };
  window.addEventListener('resize', resize, false);

  //event listener
  getEffect = function(e){
    currentEffect = e.currentTarget.value;
    checkE(e);
  };
  effectSelector.options.selectedIndex = 0;
  currentEffect = 'fog';
  effectSelector.addEventListener('change', getEffect, false);

  doButtons = function(e){
    clearSprites();
    switch(currentEffect){
      case 'clearFromCenter' :
        doClearFromCenter();
        break;
      case 'fog' :
        doFog();
        break;
      case 'starburst' :
        doStarburst();
        break;
      case 'roller' :
        doRoller();
        break;
      case 'clearCircles' :
        doClearCircles();
        break;
    }
    checkE(e);
  };
  startButton.addEventListener('click', doButtons, false);
  returnButton.addEventListener('click', doButtons, false);

  //roller animation: animate block by its height
  rollerIn = scrawl.newTween({
    name: 'rollerIn',
    start: {height: 0},
    engines: {height: 'easeOut3'},
    duration: 1000,
    killOnComplete: true,
  });
  rollerOut = scrawl.newTween({
    name: 'rollerOut',
    end: {height: 0},
    engines: {height: 'easeIn3'},
    duration: 1000,
    killOnComplete: true,
  });
  buildRoller = function(){
    switchPages();
    rollerOut.clone({
      targets: myBlock,
      start: {
        height: browserHeight,
      },
      onComplete: {
        visibility: false,
      },
      callback: function(){
        hidePad();
        scrawl.renderElements();
      },
    }).run();
  };
  doRoller = function(){
    var tween = rollerIn.clone({
      targets: myBlock,
      onCommence: {
        visibility: true,
        width: browserWidth,
        height: 0,
        startX: 0,
        startY: 0,
        handleX: 'left',
        handleY: 'top',
        scale: 1,
        globalAlpha: 1,
        roll: 0,
      },
      end: {
        height: browserHeight
      },
      onComplete: {
        height: browserHeight,
      },
      callback: function(){
        if(page1.visibility){
          newFrame();
          frame.onload = function(){
            buildRoller();
          };
          frame.src = frameSources[currentFrame];
        }
        else{
          buildRoller();
        }
      },
    });
    showPad();
    scrawl.renderElements();
    tween.run();
  };

  //starburst animation: animate star by its scale and roll
  starburstIn = scrawl.newTween({
    name: 'starburstIn',
    start: {	scale: 0.01,	roll: 0},
    end: {		scale: 2, 		roll: 180},
    engines: {	scale: 'easeOut'},
    duration: 3000,
    killOnComplete: true,
  });
  starburstOut = scrawl.newTween({
    name: 'starburstOut',
    start: {	scale: 2, 		roll: 180},
    end: {		scale: 0.01,	roll: 360},
    engines: {	scale: 'easeIn'},
    duration: 3000,
    killOnComplete: true,
  });
  buildStarburst = function(){
    switchPages();
    starburstOut.clone({
      targets: myStar,
      onComplete: {
        visibility: false,
      },
      callback: function(){
        hidePad();
        scrawl.renderElements();
      },
    }).run();
  };
  doStarburst = function(){
    var tween = starburstIn.clone({
      targets: myStar,
      onCommence: {
        visibility: true,
        startX: browserWidth/2,
        startY: browserHeight/2,
        handleX: 'center',
        handleY: 'center',
        scale: 0.01,
        globalAlpha: 1,
        roll: 0,
      },
      onComplete: {
        scale: 2,
        roll: 180,
      },
      callback: function(){
        if(page1.visibility){
          newFrame();
          frame.onload = function(){
            buildStarburst();
          };
          frame.src = frameSources[currentFrame];
        }
        else{
          buildStarburst();
        }
      },
    });
    showPad();
    scrawl.renderElements();
    tween.run();
  };

  //fog animation: white out browser - animate block by its globalAlpha
  fogIn = scrawl.newTween({
    name: 'fogIn',
    start: {globalAlpha: 0},
    end: {globalAlpha: 1},
    duration: 1000,
    killOnComplete: true,
  });
  fogOut = scrawl.newTween({
    name: 'fogOut',
    start: {globalAlpha: 1},
    end: {globalAlpha: 0},
    duration: 1000,
    killOnComplete: true,
  });
  buildFog = function(){
    switchPages();
    fogOut.clone({
      targets: myBlock,
      onComplete: {
        visibility: false,
      },
      callback: function(){
        hidePad();
        scrawl.renderElements();
      },
    }).run();
  };
  doFog = function(){
    var tween = fogIn.clone({
      targets: myBlock,
      onCommence: {
        visibility: true,
        width: browserWidth,
        height: browserHeight,
        startX: 0,
        startY: 0,
        handleX: 'left',
        handleY: 'top',
        scale: 1,
        globalAlpha: 0,
        roll: 0,
      },
      onComplete: {
        globalAlpha: 1,
      },
      callback: function(){
        if(page1.visibility){
          newFrame();
          frame.onload = function(){
            buildFog();
          };
          frame.src = frameSources[currentFrame];
        }
        else{
          buildFog();
        }
      },
    });
    showPad();
    scrawl.renderElements();
    tween.run();
  };

  //clear from center: animate block by its scale and roll
  clearFromCenterIn = scrawl.newTween({ 
    name: 'clearFromCenterIn',
    start: {	scale: 0, 	roll: 0},
    end: {		scale: 1,	roll: 360},
    duration: 1500,
    killOnComplete: true,
  });
  clearFromCenterOut = scrawl.newTween({
    name: 'clearFromCenterOut',
    start: {	scale: 1, 	roll: 0},
    end: {		scale: 0, 	roll: 360},
    duration: 1500,
    killOnComplete: true,
  });
  buildClearFromCenter = function(){
    switchPages();
    clearFromCenterOut.clone({
      targets: myBlock,
      onComplete: {
        visibility: false,
      },
      callback: function(){
        hidePad();
        scrawl.renderElements();
      },
    }).run();
  };
  doClearFromCenter = function(){
    var tween = clearFromCenterIn.clone({
      targets: myBlock,
      onCommence: {
        visibility: true,
        scale: 0,
        globalAlpha: 1,
        roll: 0,
        startX: browserWidth/2,
        startY: browserHeight/2,
        width: browserWidth * 1.2,
        height: browserHeight * 1.2,
        handleX: 'center',
        handleY: 'center',
      },
      onComplete: {
        scale: 1,
        roll: 360,
      },
      callback: function(){
        if(page1.visibility){
          newFrame();
          frame.onload = function(){
            buildClearFromCenter();
          };
          frame.src = frameSources[currentFrame];
        }
        else{
          buildClearFromCenter();
        }
      },
    });
    showPad();
    scrawl.renderElements();
    tween.run();
  };

  //clear with circles: animate circles by their scale
  clearCirclesIn = scrawl.newTween({ 
    name: 'clearCirclesIn',
    start: {scale: 0},
    end: {scale: 2},
    engines: {scale: 'easeOut4'},
    duration: 2000,
    killOnComplete: true,
  });
  clearCirclesOut = scrawl.newTween({
    name: 'clearCirclesOut',
    start: {scale: 2},
    end: {scale: 0},
    engines: {scale: 'easeIn4'},
    duration: 2000,
    killOnComplete: true,
  });
  buildClearCircles = function(){
    switchPages();
    clearCirclesOut.clone({
      targets: myCircles,
      onComplete: {
        visibility: false,
      },
      callback: function(){
        hidePad();
        scrawl.renderElements();
      },
    }).run();
  };
  doClearCircles = function(){
    var tween = clearCirclesIn.clone({
      targets: myCircles,
      onCommence: {
        visibility: true,
        scale: 0,
      },
      onComplete: {
        scale: 2,
      },
      callback: function(){
        if(page1.visibility){
          newFrame();
          frame.onload = function(){
            buildClearCircles();
          };
          frame.src = frameSources[currentFrame];
        }
        else{
          buildClearCircles();
        }
      },
    });
    for(var i = 0, iz = myCircles.length; i < iz; i++){
      myCircles[i].set({
        startX: Math.floor(Math.random() * browserWidth),
        startY: Math.floor(Math.random() * browserHeight),
      });
    }
    showPad();
    scrawl.renderElements();
    tween.run();
  };

  //canvas animation - runs all the time
  scrawl.newAnimation({
    fn: function(){
      scrawl.render();
    },
  });

  //complete initial setup of DOM elements in stack
  resize();
  scrawl.renderElements();
};

//load scrawl modules used in this demo
scrawl.loadModules({
  path: 'http://scrawl.rikweb.org.uk/js/',
  modules: ['path', 'factories', 'animation', 'stacks', 'block', 'wheel'],			
  callback: function(){
    window.addEventListener('load', function(){
      scrawl.init();
      mycode();
    }, false);
  },
});

style.css

.zero {
  margin: 0;
  padding: 0;
  border: 0;
}
.center {
  width: 100%;
  text-align: center;
}

Web-page---animated-loading-effects.markdown

Web page - animated loading effects

Uses scrawl.js to generate the loading effects

A Pen by Rik Roots on CodePen.

License.