蛇を食いしん坊にする.6

    
    


    
        for(var row=0;row<20;row++){
            document.write("<tr>");
            for(var rank=0;rank<20;rank++){
                document.write("<td></td>");
            }
            document.write("</tr>");
        }
        
    
 
        
スコア:
        

    

        
                /* */
            var snake=new Array();
                snake[0]=53;
                snake[1]=54;
                snake[2]=55;
            /* */
            var row=document.getElementsByTagName("tr");//  tr 
            var arr=new Array();
                for(var i=0;i<20;i++){
                    var rank=row[i].getElementsByTagName("td");
                    arr[i]=new Array();
                    for(var j=0;j<20;j++){
                        arr[i][j]=rank[j];
                    };
                };
                /*
                var k=0;
                for(var i=0;i<20;i++){
                    for(var j=0;j<20;j++){
                        arr[i][j].innerHTML=i+","+j+","+k;
                        k++;
                    };
                };
                */
                /* */
                function snake_show(){
                        for(var i=0;i<snake.length;i++){
                        var num = snake[i];
                        var row_num=(~~(num/20));
                        var rank_num=(num-row_num*20);
                        arr[row_num][rank_num].style.backgroundColor="red";
                    };
                }
                function snake_show_2(){
                    var snake_tail=snake[snake.length-1]
                    var snake_tail_row_num=(~~(snake_tail/20));
                    var snake_tail_rank_num=(snake_tail-snake_tail_row_num*20);
                    arr[snake_tail_row_num][snake_tail_rank_num].style.backgroundColor="";
                }
                /* */
                    var food_num=(~~(Math.random()*200))-(0);
                    function food(){
                        var food_row_num=(~~(food_num/20));
                        var food_rank_num=(food_num-food_row_num*20);
                        arr[food_row_num][food_rank_num].style.backgroundColor="blue";  
                    }
                /* */
                function direction(e){
                    switch (e){
                        case "up":
                             var num = snake[0]-20;
                            break;
                        case "left" :
                             var num = snake[0]-1;
                            break;
                        case "right" :  
                             var num = snake[0]+1;
                            break;
                        case "down" :
                            var num = snake[0]+20;
                            break;
                    }
                        snake.unshift(num);
                            snake_show_2();
                        if(food_num==num){
                            food_num=(~~(Math.random()*200));
                            food();
                        }else{
                            snake.pop();
                        }
                            snake_show();
                    }
                function score(){
                    document.getElementById("score").innerHTML=snake.length-3;
                }
                    food();
                    snake_show();
                    // 
                    console.log(snake);
                    var auto=setInterval("direction('left')",500);  
                    document.onkeydown=function(event){
                    var e = event || window.event || arguments.callee.caller.arguments[0];
                     if(e && e.keyCode==38){// 
                         window.clearInterval(auto);
                            direction("up");
                        auto=setInterval("direction('up')",500);
                         setInterval(score,500);
                     }else if(e && e.keyCode==37){
                         window.clearInterval(auto);// 
                            direction("left");
                         auto=setInterval("direction('left')",500);
                         setInterval(score,500);
                     }else if(e && e.keyCode==39){// 
                         window.clearInterval(auto);
                            direction("right");
                          auto=setInterval("direction('right')",500);
                         setInterval(score,500);
                     }else if(e && e.keyCode==40){// 
                         window.clearInterval(auto);
                            direction("down");
                         auto=setInterval("direction('down')",500);
                         setInterval(score,500);
                     }
                 };
                setInterval(score,500);