javascript实现2048游戏示例_基础知识

#div2048
{
    width: 500px;
    height: 500px;
    background-color: #b8af9e;
    margin: 0 auto;
    position: relative;
}
#start
{
    width: 500px;
    height: 500px;
    line-height: 500px;
    display: block;
    text-align: center;
    font-size: 30px;
    background: #f2b179;
    color: #FFFFFF;
}
#div2048 div.tile
{
    margin: 20px 0px 0px 20px;
    width: 100px;
    height: 40px;
    padding: 30px 0;
    font-size: 40px;
    line-height: 40px;
    text-align: center;
    float: left;
}
#div2048 div.tile0{
 background: #ccc0b2;
}
#div2048 div.tile2
{
    color: #7c736a;
    background: #eee4da;
}
#div2048 div.tile4
{
    color: #7c736a;
    background: #ece0c8;
}
#div2048 div.tile8
{
    color: #fff7eb;
    background: #f2b179;
}
#div2048 div.tile16
{
    color:#fff7eb;
    background:#f59563;
}
#div2048 div.tile32
{
    color:#fff7eb;
    background:#f57c5f;
}
#div2048 div.tile64
{
    color:#fff7eb;
    background:#f65d3b;
}
#div2048 div.tile128
{
    color:#fff7eb;
    background:#edce71;
}
#div2048 div.tile256
{
    color:#fff7eb;
    background:#edcc61;
}
#div2048 div.tile512
{
    color:#fff7eb;
    background:#ecc850;
}
#div2048 div.tile1024
{
    color:#fff7eb;
    background:#edc53f;
}
#div2048 div.tile2048
{
    color:#fff7eb;
    background:#eec22e;
}

game2048.prototype = {
 init: function(){
  for(var i = 0, len = this.tiles.length; i    var tile = this.newTile(0);
   tile.setAttribute('index', i);
   this.container.appendChild(tile);
   this.tiles[i] = tile;
  }
  this.randomTile();
  this.randomTile();
 },
 newTile: function(val){
  var tile = document.createElement('div');
  this.setTileVal(tile, val)
  return tile;
 },
 setTileVal: function(tile, val){
  tile.className = 'tile tile' + val;
  tile.setAttribute('val', val);
  tile.innerHTML = val > 0 ? val : '';
 },
 randomTile: function(){
  var zeroTiles = [];
  for(var i = 0, len = this.tiles.length; i    if(this.tiles[i].getAttribute('val') == 0){
    zeroTiles.push(this.tiles[i]);
   }
  }
  var rTile = zeroTiles[Math.floor(Math.random() * zeroTiles.length)];
  this.setTileVal(rTile, Math.random()  },
 move:function(direction){
  var j;
  switch(direction){
   case 'W':
    for(var i = 4, len = this.tiles.length; i      j = i;
     while(j >= 4){
      this.merge(this.tiles[j - 4], this.tiles[j]);
      j -= 4;
     }
    }
    break;
   case 'S':
    for(var i = 11; i >= 0; i--){
     j = i;
     while(j       this.merge(this.tiles[j + 4], this.tiles[j]);
      j += 4;
     }
    }
    break;
   case 'A':
    for(var i = 1, len = this.tiles.length; i      j = i;
     while(j % 4 != 0){
      this.merge(this.tiles[j - 1], this.tiles[j]);
      j -= 1;
     }
    }
    break;
   case 'D':
    for(var i = 14; i >= 0; i--){
     j = i;
     while(j % 4 != 3){
      this.merge(this.tiles[j + 1], this.tiles[j]);
      j += 1;
     }
    }
    break;
  }
  this.randomTile();
 },
 merge: function(prevTile, currTile){
  var prevVal = prevTile.getAttribute('val');
  var currVal = currTile.getAttribute('val');
  if(currVal != 0){
   if(prevVal == 0){
    this.setTileVal(prevTile, currVal);
    this.setTileVal(currTile, 0);
   }
   else if(prevVal == currVal){
    this.setTileVal(prevTile, prevVal * 2);
    this.setTileVal(currTile, 0);
   }
  }
 },
 equal: function(tile1, tile2){
  return tile1.getAttribute('val') == tile2.getAttribute('val');
 },
 max: function(){
  for(var i = 0, len = this.tiles.length; i    if(this.tiles[i].getAttribute('val') == 2048){
    return true;
   }
  }
 },
 over: function(){
  for(var i = 0, len = this.tiles.length; i    if(this.tiles[i].getAttribute('val') == 0){
    return false;
   }
   if(i % 4 != 3){
    if(this.equal(this.tiles[i], this.tiles[i + 1])){
     return false;
    }
   }
   if(i     if(this.equal(this.tiles[i], this.tiles[i + 4])){
     return false;
    }
   }
  }
  return true;
 },
 clean: function(){
  for(var i = 0, len = this.tiles.length; i    this.container.removeChild(this.tiles[i]);
  }
  this.tiles = new Array(16);
 }
}

var game, startBtn;

window.onload = function(){
 var container = document.getElementById('div2048');
 startBtn = document.getElementById('start');
 startBtn.onclick = function(){
  this.style.display = 'none';
  game = game || new game2048(container);
  game.init();
 }
}

window.onkeydown = function(e){
 var keynum, keychar;
 if(window.event){  // IE
  keynum = e.keyCode;
 }
 else if(e.which){  // Netscape/Firefox/Opera
  keynum = e.which;
 }
 keychar = String.fromCharCode(keynum);
 if(['W', 'S', 'A', 'D'].indexOf(keychar) > -1){
  if(game.over()){
   game.clean();
   startBtn.style.display = 'block';
   startBtn.innerHTML = 'game over, replay?';
   return;
  }
  game.move(keychar);
 }
}