var Tools = {}, // provides functions like addEvent, ... getOrigin, etc.
  startPoint,
  currentTarget,
  currentTargetHeight = 0;
/* ----------------------------------- */
/* --------- Tool Functions ---------- */
/* ----------------------------------- */
function getOrigin(elm) {
  var box = (elm.getBoundingClientRect) ? elm.getBoundingClientRect() : {
      top: 0,
      left: 0
    },
    doc = elm && elm.ownerDocument,
    body = doc.body,
    win = doc.defaultView || doc.parentWindow || window,
    docElem = doc.documentElement || body.parentNode,
    clientTop = docElem.clientTop || body.clientTop || 0, // border on html or body or both
    clientLeft = docElem.clientLeft || body.clientLeft || 0;

  return {
    left: box.left + (win.pageXOffset || docElem.scrollLeft) - clientLeft,
    top: box.top + (win.pageYOffset || docElem.scrollTop) - clientTop
  };
}

function addEvent(obj, type, func) {
  addEvent.cache = addEvent.cache ||  {
    _get: function(obj, type, func, checkOnly) {
      var cache = addEvent.cache[type] || [];

      for (var n = cache.length; n--;) {
        if (obj === cache[n].obj && '' + func === '' + cache[n].func) {
          func = cache[n].func;
          if (!checkOnly) {
            cache[n] = cache[n].obj = cache[n].func = null;
            cache.splice(n, 1);
          }
          return func;
        }
      }
    },
    _set: function(obj, type, func) {
      var cache = addEvent.cache[type] = addEvent.cache[type] || [];

      if (addEvent.cache._get(obj, type, func, true)) {
        return true;
      } else {
        cache.push({
          func: func,
          obj: obj
        });
      }
    }
  };

  if (!func.name && addEvent.cache._set(obj, type, func) || typeof func !== 'function') {
    return;
  }

  if (obj.addEventListener) obj.addEventListener(type, func, false);
  else obj.attachEvent('on' + type, func);
}

function removeEvent(obj, type, func) {
  if (typeof func !== 'function') return;
  if (!func.name) {
    func = addEvent.cache._get(obj, type, func) || func;
  }

  if (obj.removeEventListener) obj.removeEventListener(type, func, false);
  else obj.detachEvent('on' + type, func);
}

Tools.getOrigin = getOrigin;
Tools.addEvent = addEvent;
Tools.removeEvent = removeEvent;









/* ---------------------------------- */
/* ---- HSV-circle color picker ----- */
/* ---------------------------------- */

// Create HSV-circle Relavent Variables
var hsv_map = document.getElementById('hsv_map'),
  colorDiskWrapper = document.getElementById('colorDiskWrapper'),
  colorDisc = document.getElementById('surface'),
  hsv_mapCover = document.getElementById('cover'),
  hsv_mapCursor = document.getElementById('hsv-cursor'),

  luminenceBarWrapper = document.getElementById('luminenceBarWrapper'),
  hsv_barBGLayer = document.getElementById('bar-bg'),
  hsv_barWhiteLayer = document.getElementById('bar-white'),
  luminanceBar = document.getElementById('luminanceBar'),
  hsv_barcursor = document.getElementById('hsv-barcursor'),
  hsv_barCursors = document.getElementById('hsv-barcursors'),
  hsv_barCursorsCln = hsv_barCursors.className,

  luminanceBarContext = luminanceBar.getContext("2d"),
  colorDiscHeight = colorDisc.offsetHeight,
  colorDiscRadius = colorDisc.offsetHeight / 2;



// generic function for drawing a canvas disc
var drawDisk = function(ctx, coords, radius, steps, colorCallback) {
    var x = coords[0] || coords, // coordinate on x-axis
      y = coords[1] || coords, // coordinate on y-axis
      a = radius[0] || radius, // radius on x-axis
      b = radius[1] || radius, // radius on y-axis
      angle = 360,
      rotate = 0,
      coef = Math.PI / 180;

    ctx.save();
    ctx.translate(x - a, y - b);
    ctx.scale(a, b);

    steps = (angle / steps) || 360;

    for (; angle > 0; angle -= steps) {
      ctx.beginPath();
      if (steps !== 360) ctx.moveTo(1, 1); // stroke
      ctx.arc(1, 1, 1, (angle - (steps / 2) - 1) * coef, (angle + (steps / 2) + 1) * coef);

      if (colorCallback) {
        colorCallback(ctx, angle);
      } else {
        ctx.fillStyle = 'black';
        ctx.fill();
      }
    }
    ctx.restore();
  },
  drawCircle = function(ctx, coords, radius, color, width) { // uses drawDisk
    width = width || 1;
    radius = [
      (radius[0] || radius) - width / 2, (radius[1] || radius) - width / 2
    ];
    drawDisk(ctx, coords, radius, 1, function(ctx, angle) {
      ctx.restore();
      ctx.lineWidth = width;
      ctx.strokeStyle = color || '#000';
      ctx.stroke();
    });
  };

if (colorDisc.getContext) {
  drawDisk( // HSV color wheel with white center
    colorDisc.getContext("2d"), [colorDisc.width / 2, colorDisc.height / 2], [colorDisc.width / 2 - 1, colorDisc.height / 2 - 1],
    360,
    function(ctx, angle) {
      var gradient = ctx.createRadialGradient(1, 1, 1, 1, 1, 0);
      gradient.addColorStop(0, 'hsl(' + (360 - angle + 0) + ', 100%, 50%)');
      gradient.addColorStop(1, "#FFFFFF");

      ctx.fillStyle = gradient;
      ctx.fill();
    }
  );
  drawCircle( // gray border
    colorDisc.getContext("2d"), [colorDisc.width / 2, colorDisc.height / 2], [colorDisc.width / 2, colorDisc.height / 2],
    '#555',
    3
  );
}


// draw the luminanceBar bar
var gradient = luminanceBarContext.createLinearGradient(0, 0, 0, colorDiscHeight);

gradient.addColorStop(0, "transparent");
gradient.addColorStop(1, "black");

luminanceBarContext.fillStyle = gradient;
luminanceBarContext.fillRect(0, 0, luminanceBar.offsetWidth, colorDiscHeight);









// Manage Color Wheel Mouse Events
var renderHSVPicker = function(color) { // used in renderCallback of 'new ColorPicker'
  var pi2 = Math.PI * 2,
    x = Math.cos(pi2 - color.hsv.h * pi2),
    y = Math.sin(pi2 - color.hsv.h * pi2),
    r = color.hsv.s * colorDiscRadius;

  hsv_mapCover.style.opacity = 1 - color.hsv.v;

  // this is the faster version...
  hsv_barWhiteLayer.style.opacity = 1 - color.hsv.s;
  hsv_barBGLayer.style.backgroundColor = 'rgb(' +
    color.hueRGB.r + ',' +
    color.hueRGB.g + ',' +
    color.hueRGB.b + ')';

  var doc = window.document;

  hsv_mapCursor.style.left = ((x * r + colorDiscRadius + doc.body.scrollLeft + doc.documentElement.scrollLeft) - 1) + 'px';
  hsv_mapCursor.style.top = ((y * r + colorDiscRadius + doc.body.scrollTop + doc.documentElement.scrollTop) - 1) + 'px';

  hsv_mapCursor.style.borderColor = hsv_barcursor.style.borderColor = color.RGBLuminance > 0.22 ? 'black' : 'white';
  hsv_barcursor.style.top = (((1 - color.hsv.v) * colorDiscRadius * 2 + doc.body.scrollTop + doc.documentElement.scrollTop) + -7) + 'px';
};


var myColor = new Colors(),
  doRender = function(color) {
    renderHSVPicker(color);
  },
  renderTimer,
  // those functions are in case there is no ColorPicker but only Colors involved
  startRender = function(oneTime) {
    if (oneTime) { // only Colors is instanciated
      doRender(myColor.colors);
    } else {
      renderTimer = window.setInterval(
        function() {
          doRender(myColor.colors);
          // http://stackoverflow.com/questions/2940054/
        }, 13); // 1000 / 60); // ~16.666 -> 60Hz or 60fps
    }
  },
  stopRender = function() {
    window.clearInterval(renderTimer);
  };





// Create Event Functions
var hsvDown = function(e) { // mouseDown callback
    var target = e.target || e.srcElement;

    if (e.preventDefault) e.preventDefault();

    //currentTarget = target.id ? target : target.parentNode;
    if (target === hsv_mapCover || target === hsv_mapCursor || target === hsv_barcursor) {
      currentTarget = target.parentNode;
    } else if (target === hsv_barCursors) {
      currentTarget = target;
    } else {
      return;
    }

    startPoint = Tools.getOrigin(currentTarget);
    currentTargetHeight = currentTarget.offsetHeight; // as diameter of circle

    Tools.addEvent(window, 'mousemove', hsvMove);
    hsv_mapCover.style.cursor = hsv_mapCursor.style.cursor = 'none';
    hsvMove(e);
    startRender();
  },
  hsvMove = function(e) { // mouseMove callback
    var r, x, y, h, s;

    if (currentTarget === colorDiskWrapper) { // the circle
      r = currentTargetHeight / 2;
      x = e.clientX - startPoint.left - r;
      y = e.clientY - startPoint.top - r;
      h = 360 - ((Math.atan2(y, x) * 180 / Math.PI) + (y < 0 ? 360 : 0));
      s = (Math.sqrt((x * x) + (y * y)) / r) * 100;
      myColor.setColor({
        h: h,
        s: s
      }, 'hsv');
    } else if (currentTarget === hsv_barCursors) { // the luminanceBar
      myColor.setColor({
        v: (currentTargetHeight - (e.clientY - startPoint.top)) / currentTargetHeight * 100
      }, 'hsv');
    }
  };

// Initial Rendering
doRender(myColor.colors);

// Adde Events To Objects
Tools.addEvent(hsv_map, 'mousedown', hsvDown); // event delegation
Tools.addEvent(window, 'mouseup', function() {
  Tools.removeEvent(window, 'mousemove', hsvMove);
  hsv_mapCover.style.cursor = hsv_mapCursor.style.cursor = hsv_barCursors.style.cursor = 'pointer';
  stopRender();
});

#wrapper {
  width: 500px;
  height: 500px;
  background-color: pink;
}
#hsv_map {
  width: 540px;
  height: 500px;
  position: absolute;
}
#colorDiskWrapper {
  border-radius: 50%;
  position: relative;
  width: 500px;
}
#cover {
  background-color: black;
  border-radius: 50%;
  cursor: pointer;
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
}
#bar-bg,
#bar-white {
  position: absolute;
  right: 0;
  top: 0;
  width: 15px;
  height: 500px;
}
#bar-white {
  background-color: #fff;
}
#hsv-cursor {
  position: absolute;
  border: 2px solid #eee;
  border-radius: 50%;
  width: 9px;
  height: 9px;
  margin: -5px;
  cursor: pointer;
}
.no-cursor #hsv-cursor,
#hsv_map.no-cursor #cover {
  cursor: none;
  /* also works in IE8 */
  /*url(_blank.gif), url(_blank.png), url(_blank.cur), auto;*/
}
#luminanceBar {
  position: absolute;
  right: 0;
  top: 0;
}
#hsv-barcursors {
  position: absolute;
  right: -7.5px;
  width: 30px;
  top: 0;
  height: 500px;
  overflow: hidden;
  cursor: pointer;
}
#hsv-barcursor {
  position: absolute;
  right: 7.5px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  border: 2px solid black;
  margin-bottom: 5px;
}

<script src="https://rawgit.com/PitPik/colorPicker/master/colors.js"></script>
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quo no, his accusamus persequeris ea. Exerci delenit ad eos, ei sea tamquam ancillae necessitatibus. Est legere possim mnesarchum an. Vim nonumes expetendis ea, mei te mutat propriae platonem, per ut feugiat reprimique. Has deserunt nominati liberavisse
ut. Per cibo ubique omittam in, has te decore denique, justo nominavi id pro. Ei ius paulo deserunt pertinacia. Nec nostro expetenda id. Nec no esse interesset, id qui ferri errem. Qui possim ponderum platonem ea, nostro epicuri nam in. Ei consul ubique
conclusionemque eum, et alterum apeirian nam. Quem odio adipiscing has ei. Et has solum perfecto tincidunt, quo no indoctum prodesset. Pri ut tritani ceteros tractatos, in legere disputationi mea. Ne mel mutat graeci, mei eu doctus appetere. Ius dicam
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ne eos labitur pericula. Ea dicat sonet nec, te pri libris putant eirmod, ancillae voluptatibus ut eam. Dicat commune necessitatibus nec cu, an enim purto menandri vel, eu ferri altera admodum duo.
<div id="wrapper">
  <div id="hsv_map">
    <div id="colorDiskWrapper">
      <canvas id="surface" width="500" height="500"></canvas>
      <div id="cover"></div>
      <div id="hsv-cursor"></div>
    </div>
    <div id="luminenceBarWrapper">
      <div id="bar-bg"></div>
      <div id="bar-white"></div>
      <canvas id="luminanceBar" width="15" height="500"></canvas>
      <div id="hsv-barcursors" id="hsv_cursors">
        <div id="hsv-barcursor"></div>
      </div>
    </div>
  </div>
</div>