JavaScript实现打砖块游戏

 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 

 开始
 重置
 
 

 
 
 
 

window.onload = init;
 
function init(){
 var gameArea = document.getElementsByClassName("game")[0];
 var rows = 5;
 var cols = 11;
 var b_width = 50;
 var b_height = 20;
 var bricks = [];
 var speedX = 5;
 var speedY = -5;
 var interId = null;
 var lf = 0;
 var tp = 0;
 var flap
 var ball;
 var n = 0;
 
 var st = document.getElementById("start");
 var rt = document.getElementById("reset");
 var score = document.getElementById("score");
 score.innerHTML = "得分:" + n;
 
 renderDom();
 bindDom();
 
 function renderDom(){
 getBrick();
 //得到五彩砖块
 function getBrick(){
 for (var i = 0; i < rows; i++) {
 var tp = i * b_height;
 var brick = null;
 for (var j = 0; j < cols; j++) {
  var lf = j * b_width;
  brick = document.createElement("div");
  brick.className = "brick";
  brick.setAttribute("style","top:" + tp + "px;left:" + lf + "px;");
  brick.style.backgroundColor = getColor();
  bricks.push(brick);
  gameArea.appendChild(brick);
 }
 }
 }
 
 //添加挡板
 var flap = document.createElement("div");
 flap.className = "flap";
 gameArea.appendChild(flap);
 //添加挡板小球
 var ball = document.createElement("div");
 ball.className = "ball";
 gameArea.appendChild(ball);
 }
 
 function bindDom(){
 flap = document.getElementsByClassName("flap")[0];
 
 window.onkeydown = function(e){
 var ev = e || window.event;
 var lf = null;
 if (e.keyCode == 37) { //左键往左走
 lf = flap.offsetLeft - 10;
 if (lf < 0) { 
  lf = 0;
 }
 flap.style.left = lf + "px";
 
 }else if (e.keyCode == 39) { //右键往右走
 lf = flap.offsetLeft + 10;
 if (lf >= gameArea.offsetWidth - flap.offsetWidth) {
  lf = gameArea.offsetWidth - flap.offsetWidth
 }
 flap.style.left = lf + "px";
 }
 }
 
 st.onclick = function(){
 ballMove();
 st.onclick = null;
 }
 
 rt.onclick = function(){
 window.location.reload();
 }
 
 }
 
 //得到砖块的随即颜色
 function getColor(){
 var r = Math.floor(Math.random()*256);
 var g = Math.floor(Math.random()*256);
 var b = Math.floor(Math.random()*256);
 return "rgb(" + r + "," + g + "," + b +")";
 }
 //实现小球上下左右来回运动
 function ballMove(){
 ball = document.getElementsByClassName("ball")[0];
 
 interId = setInterval(function(){
 lf = ball.offsetLeft + speedX;
 tp = ball.offsetTop + speedY;
 //实现砖块消失的效果
 for (var i = 0; i < bricks.length; i++) {
 var bk = bricks[i];
 if ((lf + ball.offsetWidth/2) >= bk.offsetLeft
  && (lf + ball.offsetWidth/2) <= (bk.offsetLeft + bk.offsetWidth)
  && (bk.offsetTop + bk.offsetHeight) >= ball.offsetTop
 ) {
  bk.style.display = "none";
  speedY = 5;
  n++;
  score.innerHTML = "得分:"+n;
 }
 }
 
 if (lf < 0) {
 speedX = -speedX;
 }
 if (lf >= (gameArea.offsetWidth - ball.offsetWidth)){ 
 speedX = -speedX;
 }
 if (tp <= 0) {
 speedY = 5;
 }else if((ball.offsetTop + ball.offsetHeight) >= flap.offsetTop
  && (ball.offsetLeft + ball.offsetWidth/2) >= flap.offsetLeft
  && (ball.offsetLeft + ball.offsetWidth/2) <= (flap.offsetLeft + flap.offsetWidth)
 ){
 speedY = -5;
 }else if(ball.offsetTop >= flap.offsetTop){
 gameOver();
 }
 ball.style.left = lf + 'px';
 ball.style.top = tp + "px";
 },20)
 }
 
 //判断游戏是否结束
 function gameOver(){
 alert("game over" + "\n" + "您的得分是" + score.innerHTML);
 clearInterval(interId);
 }
 
}