The full version of JavaScript Snake is fully annotated and object-oriented
Copy the code code as follows:
<html>
<head>
<title>Snake v2.4</title>
<style>
body{
font-size:9pt;
}
table{
border-collapse: collapse;
border:solid #333 1px;
}
td{
height: 10px;
width: 10px;
font-size: 0px;
}
.filled{
background-color:blue;
}
</style>
</head>
<script>
function $(id){return document.getElementById(id);}
/****************************************************** *************
* javascript snake v2.4 <br />
* v2.4 corrected the snake body color to move as the snake moves forward
*************************************************** ************/
//Greedy snakes
var Snake = {
tbl: null,
/**
* body: snake body, each section of the snake is placed in the array,
* Data structure {x:x0, y:y0, color:color0},
* x, y represents coordinates, color represents color
**/
body: [],
//The current direction of movement, the values 0, 1, 2, 3, respectively represent up, right, down, left, press the keyboard direction keys to change it
direction: 0,
// timer
timer: null,
//speed
speed: 250,
//Whether it has been paused
paused: true,
//number of rows
rowCount: 30,
//Number of columns
colCount: 30,
//initialization
init: function(){
var colors = ['red','orange','yellow','green','blue','purple','#ccc'];
this.tbl = $("main");
var x = 0;
var y = 0;
var colorIndex = 0;
//Generate initial movement direction
this.direction = Math.floor(Math.random()*4);
//Construct table
for(var row=0;row<this.rowCount;row++){
var tr=this.tbl.insertRow(-1);
for(var col=0;col<this.colCount;col++) {
var td=tr.insertCell(-1);
}
}
//Generate 20 loose nodes
for(var i=0; i<10; i++){
x = Math.floor(Math.random()*this.colCount);
y = Math.floor(Math.random()*this.rowCount);
colorIndex = Math.floor(Math.random()*7);
if(!this.isCellFilled(x,y)){
this.tbl.rows[y].cells[x].style.backgroundColor = colors[colorIndex];
}
}
//generate snake head
while(true){
x = Math.floor(Math.random()*this.colCount);
y = Math.floor(Math.random()*this.rowCount);
if(!this.isCellFilled(x,y)){
this.tbl.rows[y].cells[x].style.backgroundColor = "black";
this.body.push({x:x,y:y,color:'black'});
break;
}
}
this.paused = true;
//Add keyboard event
document.onkeydown= function(e){
if (!e)e=window.event;
switch(e.keyCode | e.which | e.charCode){
case 13: {
if(Snake.paused){
Snake.move();
Snake.paused = false;
}
else{
//If there is no pause, stop moving
Snake.pause();
Snake.paused = true;
}
break;
}
case 37:{//left
//Stop the snake from walking backwards
if(Snake.direction==1){
break;
}
Snake.direction = 3;
break;
}
case 38:{//up
//Shortcut keys work here
if(event.ctrlKey){
Snake.speedUp(-20);
break;
}
if(Snake.direction==2){//Prevent the snake from walking backwards
break;
}
Snake.direction = 0;
break;
}
case 39:{//right
if(Snake.direction==3){//Prevent the snake from walking backwards
break;
}
Snake.direction = 1;
break;
}
case 40:{//down
if(event.ctrlKey){
Snake.speedUp(20);
break;
}
if(Snake.direction==0){//Prevent the snake from walking backwards
break;
}
Snake.direction = 2;
break;
}
}
}
},
//move
move: function(){
this.timer = setInterval(function(){
Snake.erase();
Snake.moveOneStep();
Snake.paint();
}, this.speed);
},
//Move one section of the body
moveOneStep: function(){
if(this.checkNextStep()==-1){
clearInterval(this.timer);
alert("Game over!/nPress Restart to continue.");
return;
}
if(this.checkNextStep()==1){
var _point = this.getNextPos();
var _x = _point.x;
var _y = _point.y;
var _color = this.getColor(_x,_y);
this.body.unshift({x:_x,y:_y,color:_color});
//Because one food is eaten, another food is generated
this.generateDood();
return;
}
//window.status = this.toString();
var point = this.getNextPos();
//Keep the color of the first section
var color = this.body[0].color;
//Color moves forward
for(var i=0; i<this.body.length-1; i++){
this.body[i].color = this.body[i+1].color;
}
//Subtract one section from the snake's tail and add one section to the snake's tail to show the effect of the snake moving forward.
this.body.pop();
this.body.unshift({x:point.x,y:point.y,color:color});
//window.status = this.toString();
},
//Explore where to go next
pause: function(){
clearInterval(Snake.timer);
this.paint();
},
getNextPos: function(){
var x = this.body[0].x;
var y = this.body[0].y;
var color = this.body[0].color;
//up
if(this.direction==0){
y--;
}
//To the right
else if(this.direction==1){
x++;
}
//down
else if(this.direction==2){
y++;
}
//left
else{
x--;
}
//Return a coordinate
return {x:x,y:y};
},
//Check what is the next step to move to
checkNextStep: function(){
var point = this.getNextPos();
var x = point.x;
var y = point.y;
if(x<0||x>=this.colCount||y<0||y>=this.rowCount){
return -1;//When the boundary is touched, the game ends
}
for(var i=0; i<this.body.length; i++){
if(this.body[i].x==x&&this.body[i].y==y){
return -1;//When it touches your own body, the game ends
}
}
if(this.isCellFilled(x,y)){
return 1;//There is something
}
return 0;//open space
},
//Erase the snake body
erase: function(){
for(var i=0; i<this.body.length; i++){
this.eraseDot(this.body[i].x, this.body[i].y);
}
},
//Draw the snake body
paint: function(){
for(var i=0; i<this.body.length; i++){
this.paintDot(this.body[i].x, this.body[i].y,this.body[i].color);
}
},
//Erase a section
eraseDot: function(x,y){
this.tbl.rows[y].cells[x].style.backgroundColor = "";
},
paintDot: function(x,y,color){
this.tbl.rows[y].cells[x].style.backgroundColor = color;
},
//Get the color at a coordinate
getColor: function(x,y){
return this.tbl.rows[y].cells[x].style.backgroundColor;
},
//for debugging
toString: function(){
var str = "";
for(var i=0; i<this.body.length; i++){
str += "x:" + this.body[i].x + " y:" + this.body[i].y + " color:" + this.body[i].color + " - ";
}
return str;
},
//Check whether a coordinate point is filled
isCellFilled: function(x,y){
if(this.tbl.rows[y].cells[x].style.backgroundColor == ""){
return false;
}
return true;
},
//restart
restart: function(){
if(this.timer){
clearInterval(this.timer);
}
for(var i=0; i<this.rowCount;i++){
this.tbl.deleteRow(0);
}
this.body = [];
this.init();
this.speed = 250;
},
//accelerate
speedUp: function(time){
if(!this.paused){
if(this.speed+time<10||this.speed+time>2000){
return;
}
this.speed +=time;
this.pause();
this.move();
}
},
//Produce food.
generateDood: function(){
var colors = ['red','orange','yellow','green','blue','purple','#ccc'];
var x = Math.floor(Math.random()*this.colCount);
var y = Math.floor(Math.random()*this.rowCount);
var colorIndex = Math.floor(Math.random()*7);
if(!this.isCellFilled(x,y)){
this.tbl.rows[y].cells[x].style.backgroundColor = colors[colorIndex];
}
}
};
</script>
<body onload="Snake.init();">
/****************************************************** ************<br />
* javascript snake v2.4<br />
*************************************************** ************/<br />
<table id="main" cellspacing="0" cellpadding="0"></table>
<input type="button" id="btn" value="Start/Pause" />Click the left button or press Enter to start/pause the game<br />
<input type="button" id="reset" value="Start over" /><br />
<input type="button" id="upSpeed" value="Accelerate" />Click the left button or press Ctrl + ↑ to accelerate<br />
<input type="button" id="downSpeed" value="Slow down" />Click the left button or press Ctrl + ↓ to slow down
<script>
$('btn').onclick = function(){
if(Snake.paused){
Snake.move();
Snake.paused = false;
}
else{
Snake.pause();
Snake.paused = true;
}
};
$("reset").onclick = function(){
Snake.restart();
this.blur();
};
$("upSpeed").onclick = function(){
Snake.speedUp(-20);
};
$("downSpeed").onclick = function(){
Snake.speedUp(20);
};
</script>
</body>
</html>