text: window.onload=function(){
              var container = document.getElementById("container");
              var startGame = document.getElementById("startGame");
              startGame.onclick = function(){
                  this.style.display = "none";
                  beeGame.init("container");
              }
              var beeGame;
              beeGame = {
                  enemy: {e1: {name: "e1", style: "e1", blood: 1, speed: 2,score:1},
                      e2: {name: "e2", style: "e2", blood: 2, speed: 3,score:2},
                      e3: {name: "e3", style: "e3", blood: 3, speed: 5,score:3}},
                  levelInfo: [
                      {times:3000,speed: 1, count: 10, enemy: eval("[" + new Array(11).join("'e2',") + new Array(10).join("'e1',") + "'e1'" + "]")},
                      {times:2000,speed: 2, count: 10, enemy: eval("[" + new Array(21).join("'e2',") + new Array(40).join("'e1',") + "'e1'" + "]")},
                      {times:1500,speed: 3, count: 10, enemy: eval("[" + new Array(31).join("'e2',") + new Array(30).join("'e1',") + "'e1'" + "]")}
                  ],
                  level: 0,
                  lis: [],
                  arr:[],
                  score:0,
                  init: function (parentId) {
                      this.parentDocument = document.getElementById(parentId);
                      this.createEnemy();
                      this.createPlane();
                  },
                  createEnemy: function () {
                      var ul = document.createElement("ul");
                      ul.id = "bee";
                      for (var i = 0; i < this.levelInfo[this.level].enemy.length; i++) {
                          var li = document.createElement("li");
                          li.className = this.levelInfo[this.level].enemy[i];
                          li.blood = this.enemy[this.levelInfo[this.level].enemy[i]].blood;
                          li.score = this.enemy[this.levelInfo[this.level].enemy[i]].score;
                          li.speed = this.enemy[this.levelInfo[this.level].enemy[i]].speed;
                          ul.appendChild(li);
                      }
                      this.parentDocument.appendChild(ul);
  
                      ul.style.width = (li.offsetWidth + 2) * this.levelInfo[this.level].count + 'px';
                      ul.style.left = (this.parentDocument.offsetWidth - ul.offsetWidth) / 2 + 'px';
                      this.lis=ul.getElementsByTagName("li");
                      for(var i = 0 ; i < this.lis.length;i++){
                          this.arr.push([this.lis[i].offsetLeft,this.lis[i].offsetTop]);
                      }
  
                      for(var i = 0 ; i < this.lis.length;i++){
                          this.lis[i].style.position = 'absolute';
                          this.lis[i].style.left = this.arr[i][0] + 'px';
                          this.lis[i].style.top = this.arr[i][1] + 'px';
                      }
                      this.moveBee(ul);
                      var This = this;
                      this.ul = ul;
                      this.ul.timer2 = setInterval(function(){
                          This.oneMove();
                      },this.levelInfo[this.level].times);
  
                  },
                  moveBee: function (ul) {
                      var This = this;
                      ul.timer = setInterval(function () {
                          ul.style.left = This.levelInfo[This.level].speed + ul.offsetLeft + 'px';
                          if (ul.offsetLeft + ul.offsetWidth > This.parentDocument.offsetWidth || ul.offsetLeft <= 0) {
                              ul.style.top = ul.offsetTop + This.lis[0].offsetHeight + 'px';
                              This.levelInfo[This.level].speed = 0 - This.levelInfo[This.level].speed;
                          }
                      }, 30);
                  },
                  oneMove:function(){
                      var index = Math.floor(Math.random()*this.lis.length)
                      var nowBee = this.lis[index];
                      var This = this;
                      this.lis[index].timer = setInterval(function(){
                          var a = (This.plane.offsetLeft + This.plane.offsetWidth/2) - (nowBee.offsetLeft + nowBee.offsetWidth/2 + nowBee.parentNode.offsetLeft);
                          var b = (This.plane.offsetTop + This.plane.offsetHeight/2) - (nowBee.offsetTop + nowBee.offsetHeight/2 + nowBee.parentNode.offsetTop);
                          var c = Math.sqrt(a*a + b*b);
                          var speedX = nowBee.speed * a/c;
                          var speedY = nowBee.speed * b/c;
  
                          nowBee.style.left = nowBee.offsetLeft + speedX + 'px';
                          nowBee.style.top = nowBee.offsetTop + speedY + 'px';
  
                          if((nowBee.offsetTop + nowBee.offsetHeight + nowBee.parentNode.offsetTop)>=(This.parentDocument.offsetHeight - This.plane.offsetHeight)){
                              This.gameOver();
                          }
                      },30);
                  },
                  createPlane: function () {
                      var This = this;
                      this.plane = document.createElement("div");
                      this.plane.id = 'plane';
                      this.parentDocument.appendChild(this.plane);
                      this.plane.style.left = (this.parentDocument.offsetWidth - this.plane.offsetWidth) / 2 + 'px';
                      this.plane.style.top = this.parentDocument.offsetHeight - this.plane.offsetHeight + 'px';
                      this.bindPlane();
                  },
                  bindPlane:function(){
                      var This = this;
                      document.onkeydown = function (e) {
                          if (!This.plane.timer) {
                              if (e.keyCode == '37') {
                                  This.plane.timer = setInterval(function () {
                                      if (This.plane.offsetLeft >= 10) {
                                          This.plane.style.left = This.plane.offsetLeft - 10 + 'px';
                                      }
                                  }, 30);
                              } else if (e.keyCode == '39') {
                                  This.plane.timer = setInterval(function () {
                                      if (This.plane.offsetLeft + This.plane.offsetWidth <= This.parentDocument.offsetWidth - 10) {
                                          This.plane.style.left = This.plane.offsetLeft + 10 + 'px';
                                      }
                                  }, 30);
                              }
                          }
                      }
                      document.onkeyup = function (e) {
                          clearInterval(This.plane.timer);
                          This.plane.timer = null;
                          if (e.keyCode == '32') {
                              This.createBuulet();
                          }
                      }
                  },
                  createBuulet: function () {
                      var This = this;
                      var bullet = document.createElement("div");
                      bullet.className = "bullet";
                      this.parentDocument.appendChild(bullet);
                      bullet.style.top = this.plane.offsetTop - bullet.offsetHeight + 'px';
                      bullet.style.left = this.plane.offsetLeft + this.plane.offsetWidth / 2 + 'px';
                      bullet.name="bullet";
                      This.runBullet(bullet);
  
                  },
                  runBullet:function(bullet){
                      var This = this;
                      bullet.timer = setInterval(function () {
                          bullet.style.top = bullet.offsetTop - 10 + 'px';
                          if (bullet.offsetTop <= 0) {
                              clearInterval(bullet.timer);
                              This.parentDocument.removeChild(bullet);
                          } else {
                              for (var i = 0; i < This.lis.length; i++) {
                                  var bee = This.lis[i];
                                  if (This.checkCrash(bullet, bee)) {
                                      bee.blood--;
                                      if(bee.blood ==0){
                                          clearInterval(bee.timer);
                                          This.ul.removeChild(bee);
                                          This.score += bee.score;
                                          document.getElementsByTagName("span")[0].innerHTML = This.score;
                                      }
                                      clearInterval(bullet.timer);
                                      This.parentDocument.removeChild(bullet);
                                      if(This.lis.length == 0){
                                          This.nextLevel();
                                      }
  
                                  }
                              }
                          }
  
  
                      }, 30);
                  },
                  checkCrash: function (bullet, bee) {
                      var l1 = bullet.offsetLeft;
                      var r1 = bullet.offsetLeft + bullet.offsetWidth;
                      var t1 = bullet.offsetTop;
                      var b1 = bullet.offsetTop + bullet.offsetHeight;
                      var l2 = bee.offsetLeft + bee.parentNode.offsetLeft;
                      var r2 = bee.offsetLeft + bee.offsetWidth + bee.parentNode.offsetLeft;
                      var t2 = bee.offsetTop + bee.parentNode.offsetTop;
                      var b2 = bee.offsetTop + bee.offsetHeight + bee.parentNode.offsetTop;
                      if (r1 < l2 || l1>r2 || t1 > b2 || b1 < t2) {
                          return false;
                      } else {
                          return true;
                      }
                  },
                  gameOver:function(){
                      clearInterval(this.ul.timer2);
                      clearInterval(this.ul.timer);
                      for(var i = 0 ; i < this.lis.length ;i ++){
                          var li = this.lis[i];
                          clearInterval(li.timer);
                      }
                      var bullets = document.getElementsByClassName("bullet");
                      for(var i = 0 ;i< bullets.length ; i ++){
                          clearInterval((bullets[i].timer));
                      }
                      document.getElementById("gameOver").style.display="block";
                      document.onkeydown = function(){
  
                      };
                      document.onkeyup = function(){
  
                      }
                     // window.location.reload();
                 },
                  nextLevel:function(){
                      this.level ++;
                      this.createEnemy();
                  }
              };
          }
          function restart(){
              window.location.reload();
          }