JavaScript实现网页贪吃蛇游戏

本文实例为大家分享了JavaScript实现网页贪吃蛇游戏的具体代码，供大家参考，具体内容如下

<!DOCTYPE html>
<html>
<head><title>贪吃蛇</title>
</head>
<body>
<canvas id="canvas" width="400" height="400"></canvas>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.js"></script>
<script>
var canv=document.getElementById("canvas");
var ctx=canv.getContext("2d");
var score=0;
//定义一个方块的构造函数
var Block=function(col,row,size)
{
  this.col=col;
  this.row=row;
  this.size=size;
    };
//定义Block函数的原型方法draw；
Block.prototype.draw =function()
{
  ctx.fillRect(this.col*this.size,this.row*this.size,this.size,this.size)
   }
//定义对象蛇
var snake ={
  body:[
    new Block(20,20,10),
    new Block(20,21,10),
    new Block(20,22,10)
   ],
  direction:"right",
  };

//定义画蛇的函数
snake.draw=function()
{
   for(var i=0;i<this.body.length;i++)
  {
     this.body[i].draw();
        }
   };

snake.move = function()
         {
          var head = this.body[0];

if(snake.direction=="right")
     {
     var newhead=new Block(head.col+1,head.row,head.size)
            }

  if(snake.direction =="left")

     {
     var newhead = new Block(head.col-1,head.row,head.size);
           }
 if(snake.direction=="up")
     {
     var newhead=new Block(head.col,head.row-1,head.size)
           }
    if(snake.direction=="down")
     {
     var newhead=new Block(head.col,head.row+1,head.size)
           }
          if(newhead.col<0 || newhead.col>39 )
          {
           clearInterval(intervalId);
           gameover();
          }

          if(newhead.row<0 || newhead.row>39 )
          {
           clearInterval(intervalId);
           gameover();
          }
 for(var i=0;i<this.body.length;i++)
{
    if(this.body[i].col==newhead.col &&this.body[i].row==newhead.row)
  {
    clearInterval(intervalId);
    gameover();
      }
          }
     this.body.unshift(newhead);
     if(newhead.col==apple.posX &&newhead.row==apple.posY)
{
    score=score+100;
    while(true)
  {
     var checkApple =false;
     apple.posX=Math.floor(Math.random()*40);
     apple.posY=Math.floor(Math.random()*40);
     for(var i=0; i<this.body.length;i++)
   {
     if(this.body[i].col==apple.posX &&this.body[i].row==apple.posY)
          checkApple=true;
                        }
       if(!checkApple)
       break;
      }
  }
else{
     this.body.pop();
        }
         };
//创建苹果对象
var apple={
    posX:Math.floor(Math.random()*40),
    posY:Math.floor(Math.random()*40),
    sizeR:5
}
//画苹果函数
apple.draw=function()
{
  ctx.fillStyle="Green";
  ctx.beginPath();
  ctx.arc(this.posX*10+5,this.posY*10+5,5,0,Math.PI*2,false);
  ctx.fill();
  ctx.fillStyle="Black";
     };
//结束
var gameover=function()
{
  ctx.font="60px Comic Sans MS";
  ctx.textAlign="center";
  ctx.textBaseline="middle";
  ctx.fillText("GAME OVER!",200,200)
    };
//定时功能
var intervalId=setInterval (function ()
{
   ctx.clearRect(0,0,400,400);
   ctx.font="20px Arial";
   ctx.fillText("Score:"+score,5,15);
   snake.draw();
   snake.move();
   apple.draw();
   ctx.strokeRect(0,0,400,400);
    },200);
//贪吃蛇的按键控制
$("body").keydown(function(event)
{
   console.log(event.keyCode);
    if(event.keyCode==37 &&snake.direction!="right")
     {
    snake.direction="left";
         }
    if(event.keyCode==38 &&snake.direction!="down")
     {
    snake.direction="up";
        }
    if(event.keyCode==39 &&snake.direction!="left")
     {
     snake.direction="right";
         }
     if(event.keyCode==40 &&snake.direction!="up")
     {
     snake.direction="down";
         }
              }
);
</script>
</body>
</html>

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