var WINDOW_WIDTH = 1024;

var WINDOW_HEIGHT = 768;

var RADIUS = 8;

var MARGIN_TOP = 60;

var MARGIN_LEFT = 30;

const endTime = new Date("2016/06/17, 18:47:52");

 var curShowTimeSeconds = 0;

window.onload = function () {

  var canvas = document.getElementById('canvas');

  var context = canvas.getContext("2d");

  canvas.width = WINDOW_WIDTH;

  canvas.height = WINDOW_HEIGHT;

  curShowTimeSeconds = getCurrentShowTimeSeconds();

  render(context);

}

function getCurrentShowTimeSeconds() {

  var curTime = new Date();

  var ret = curTime.getTime() - endTime.getTime();

  ret = Math.round(ret / 1000);

  return ret >= 0 ? ret : 0;

}

function render(cxt) {

  var hours = parseInt(curShowTimeSeconds / 3600);

  var minutes = parseInt((curShowTimeSeconds - hours*3600 )/ 60);

  var seconds = curShowTimeSeconds % 60;

  renderDigit(MARGIN_LEFT, MARGIN_TOP, parseInt(hours / 10), cxt)

  renderDigit(MARGIN_LEFT + 15 * (RADIUS + 1), MARGIN_TOP, parseInt(hours % 10), cxt)

  renderDigit(MARGIN_LEFT + 30 * (RADIUS + 1), MARGIN_TOP, 10, cxt)

  renderDigit(MARGIN_LEFT + 39 * (RADIUS + 1), MARGIN_TOP, parseInt(minutes / 10), cxt);

  renderDigit(MARGIN_LEFT + 54 * (RADIUS + 1), MARGIN_TOP, parseInt(minutes % 10), cxt);

  renderDigit(MARGIN_LEFT + 69 * (RADIUS + 1), MARGIN_TOP, 10, cxt);

  renderDigit(MARGIN_LEFT + 78 * (RADIUS + 1), MARGIN_TOP, parseInt(seconds / 10), cxt);

  renderDigit(MARGIN_LEFT + 93 * (RADIUS + 1), MARGIN_TOP, parseInt(seconds % 10), cxt);

}

function renderDigit(x, y, num, cxt) {

  cxt.fillStyle = "rgb(0,102,153)";

  for (var i = 0; i < digit[num].length; i++)

    for (var j = 0; j < digit[num][i].length; j++)

      if (digit[num][i][j] == 1) {

        cxt.beginPath();

        cxt.arc(x + j * 2 * (RADIUS + 1) + (RADIUS + 1), y + i * 2 * (RADIUS + 1) + (RADIUS + 1), RADIUS, 0, 2 * Math.PI)

        cxt.closePath()

        cxt.fill()

      }

}

哪里有问题么