JS拼图游戏面向对象，注释完整。_javascript技巧

转载请注明来自http://blog.csdn.net/sunxing007




//ie7以下默认不缓存背景图像，造成延迟和闪烁，修正此bug.
//（csdn网友wtcsy提供http://blog.csdn.net/wtcsy/）
try{
document.execCommand("BackgroundImageCache", false, true);
}catch(e){alert(e)};
//辅助函数
function $(id){return document.getElementById(id)};
/*************************************************
* js拼图游戏 v1.6
* 作者 sunxing007
* 转载请注明来自http://blog.csdn.net/sunxing007
**************************************************/
var PicGame = {
//行数
x: 3,
//列数
y: 3,
//图片源
img: $('img'),
//单元格高度
cellHeight: 0,
//单元格宽度
cellWidth: 0,
//本游戏最主要的对象：表格，每个td对应着一个可以移动的小格子
board: $('board'),
//初始函数
init: function(){
//确定拼图游戏的行数和列数
this.x = $('lines').value>1?$('lines').value : 3;
this.y = $('cols').value>1?$('cols').value : 3;
//删除board原有的行
while(this.board.rows.length>0){
this.board.deleteRow(0);
}
//按照行数和列数重新构造board
for(var i=0; i var tr = this.board.insertRow(-1);
for(var j=0; j var td=tr.insertCell(-1);
}
}
//计算单元格高度和宽度
this.cellHeight = this.img.height/this.x;
this.cellWidth = this.img.width/this.y;
//获取所有的td
var tds = this.board.getElementsByTagName('td');
//对每个td， 设置样式
for(var i=0; i tds[i].style.width = this.cellWidth;
tds[i].style.height = this.cellHeight;
tds[i].style.background = "url(" + this.img.src + ")";
tds[i].style.border = "solid #ccc 1px";
var currLine = parseInt(i/this.y);
var currCol = i%this.y;
//这里最重要，计算每个单元格的背景图的位置，使他们看起来像一幅图像
tds[i].style.backgroundPositionX = -this.cellWidth * currCol;
tds[i].style.backgroundPositionY = -this.cellHeight * currLine;
}
/** begin: 打乱排序*******************/
/**
* 打乱排序的算法是这样的：比如我当前是3*3布局，
* 则我为每一个td产生一个目标位置，这些目标位置小于9且各不相同，
* 然后把它们替换到那个地方。
**/

//目标位置序列
var index = [];
index[0] = Math.floor(Math.random()*(this.x*this.y));
while(index.length<(this.x*this.y)){
var num = Math.floor(Math.random()*(this.x*this.y));
for(var i=0; i if(index[i]==num){
break;
}
}
if(i==index.length){
index[index.length] = num;
}
//window.status = index;
}
var cloneTds = [];
//把每个td克隆， 然后依据目标位置序列index，替换到目标位置
for(var i=0; i cloneTds.push(tds[i].cloneNode(true));
}
for(var i=0; i tds[i].parentNode.replaceChild(cloneTds[index[i]],tds[i]);
}
/** end: 打乱排序*********************/

//为每个td添加onclick事件。
tds = this.board.getElementsByTagName('td');
for(var i=0; i tds[i].onclick = function(){
//被点击对象的坐标
var row = this.parentNode.rowIndex;
var col = this.cellIndex;
//window.status = "row:" + row + " col:" + col;
//空白方块的坐标
var rowBlank = 0;
var colBlank = 0;
//reachable表示当前被点击的方块是否可移动
var reachable = false;
if(row+1 rowBlank = row + 1;
colBlank = col;
reachable = true;
//window.status +=" reachable! rowBlank: " + rowBlank + " colBlank:" + colBlank;
}
else if(row-1>=0 && PicGame.board.rows[row-1].cells[col].style.background == ''){
rowBlank = row - 1;
colBlank = col;
reachable = true;
//window.status +=" reachable! rowBlank: " + rowBlank + " colBlank:" + colBlank;
}
else if(col+1 rowBlank = row;
colBlank = col + 1;
reachable = true;
//window.status +=" reachable! rowBlank: " + rowBlank + " colBlank:" + colBlank;
}
else if(col-1>=0 && PicGame.board.rows[row].cells[col-1].style.background == ''){
rowBlank = row;
colBlank = col - 1;
reachable = true;
//window.status +=" reachable! rowBlank: " + rowBlank + " colBlank:" + colBlank;
}
else{
//window.status +=" unreachable!";
reachable = false;
}
//如果可移动，则把当前方块和空白方块交换
if(reachable){
var tmpBlankNode = PicGame.board.rows[rowBlank].cells[colBlank].cloneNode(true);
//需要注意的是克隆对象丢失了onclick方法，所以要补上
tmpBlankNode.onclick = arguments.callee;
var tmpCurrNode = PicGame.board.rows[row].cells[col].cloneNode(true);
tmpCurrNode.onclick = arguments.callee;
PicGame.board.rows[rowBlank].cells[colBlank].parentNode.replaceChild(tmpCurrNode,PicGame.board.rows[rowBlank].cells[colBlank]);
PicGame.board.rows[row].cells[col].parentNode.replaceChild(tmpBlankNode, PicGame.board.rows[row].cells[col]);
}
}
}
}
};
PicGame.init();
$('start').onclick = function(){
PicGame.init();
}