不用循环数组，js+html实现贪吃蛇-编程知识

不用循环数组，js+html实现贪吃蛇

功能描述：每走10步随机改变一个方方向，当键盘按下方向键 w,s,a,d时，使用键盘方向控制蛇的移动，蛇头每撞到一次自身时改变屏幕颜色，蛇头碰到边界时从另一边回来。

实现思路：用个30大小的数组存放每个结点，蛇头结点根据当前方向移动，数组中其他结点的值依次换成上一个结点的值。

效果展示：
在这里插入图片描述

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body><script>const NORTH = 0;const SOUTH = 1;const WEST = 2;const EAST = 3;const NODE_LENGTH = 50;const MAX_LENGTH = 30;const CURRENT_LENGTH = 30;const SPEED = 50;const SCREEN_WIDTH = window.innerWidth;const SCREEN_HEIGHT = window.innerHeight;var x=0;var y=0;var head = 0;var tail = MAX_LENGTH - 1;var body = [];var direction = 1;var count = 0;var touchSelfCnt = 0;var colorArray = ['red','orange','yellow','green','#025CBD','#05BC67','#6C6783','#766783','#836783','#836776','white'];var KEY_CONTROL_FLAG = 0;for (var i = 0; i <MAX_LENGTH ; i++) {console.log();var element = document.createElement("span");element.id = i;element.style.position = 'absolute';element.style.left = i*NODE_LENGTH+'px';element.style.top = 0;element.style.background ='black';element.style.border='2px solid red';element.style.width=NODE_LENGTH+'px';element.style.height=NODE_LENGTH+'px';var docBody = document.body;docBody.appendChild(element);body[i] = {x:i*NODE_LENGTH,y:0,element:element};console.log(element);}console.log(SCREEN_WIDTH,SCREEN_HEIGHT);document.addEventListener("keydown",function (event) {KEY_CONTROL_FLAG = 1;switch (event.keyCode) {case 87:direction = NORTH;break;case 83:direction = SOUTH;break;case 65:direction = WEST;break;case 68:direction = EAST;break;default:break;}});function move(){if(count%10===0 && KEY_CONTROL_FLAG===0){direction = Math.floor(Math.random()*4)}console.log('direction',direction);switch (direction) {case NORTH:y-=SPEED;break;case SOUTH:y+=SPEED;break;case WEST:x-=SPEED;break;case EAST:x+=SPEED;break;default:break;}if (x > (SCREEN_WIDTH-NODE_LENGTH)) {x = 0;}else if (y > SCREEN_HEIGHT-NODE_LENGTH) {y = 0;}else if (x < 0) {x = SCREEN_WIDTH-NODE_LENGTH;}else if (y < 0) {y = SCREEN_HEIGHT-NODE_LENGTH;}body[0] = {x:x,y:y};// console.log('x,y,direction',x,y,direction)//判断有没有撞到自己for (var i = 1; i <body.length ; i++) {if(body[i].x ===x && body[i].y===y){document.body.style.background = colorArray[touchSelfCnt%11];touchSelfCnt++;document.body.appendChild(div);}}}function drawSnake(){for (var i = body.length-1; i >0 ; i--) {body[i] = body[i-1];}for (var i = 0; i <body.length ; i++) {var element = document.getElementById(i);element.style.left = body[i].x+"px";element.style.top = body[i].y+"px";}}setInterval(function () {move();drawSnake();count++;},100)
</script>
</body>
</html>