SOURCE

console 命令行工具 X clear

                    
>
console
var guesses=0;
var message="Guess The Letter From a to z";
var letters=['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];
var today=new Date();
var letterToGuess='';
var higherOrLower='';
var lettersGuessed;
var gameOver=false;
window.onload=initGame;
function initGame(){
  var canvas=document.getElementById('canvas');
	var ctx=canvas.getContext('2d');
  var formElement=document.getElementById('createImageData');
  formElement.addEventListener('click',createImageDataPressed, false);
  // 找出随机字母
  var letterIndex=Math.floor(Math.random()*letters.length);
  letterToGuess=letters[letterIndex];
  guesses=0;
  lettersGuessed=[];
  gameOver=false;
  // 检测按下的字母
  window.addEventListener("keydown",eventKeyPressed, true);
  drawScreen();
  function createImageDataPressed(e){
    window.open(canvas.toDataURL())
  }
  function eventKeyPressed(e){
    if(!gameOver){
      // 转换为字母表中的字母,便于和letterToGuess中字母比较
      var letterPressed=String.fromCharCode(e.keyCode);
      letterPressed=letterPressed.toLowerCase();
      // 猜测次数
      guesses++;
      lettersGuessed.push(letterPressed);
      if(letterPressed==letterToGuess){ // 猜对了
        gameOver=true;
      }else{
        letterIndex=letters.indexOf(letterToGuess);
        guessIndex=letters.indexOf(letterPressed);
        if(guessIndex<0){
          higherOrLower="That is not a letter";
        }else if(guessIndex>letterIndex){
          higherOrLower="Lower";
        }else{
          higherOrLower="Higher";
        }
      }
      drawScreen();
    }
  }
  function drawScreen(){
    ctx.fillStyle="#ffa";
    ctx.fillRect(0,0,500,300);
    ctx.strokeStyle="#000";
    ctx.strokeRect(5,5,490,290);
    ctx.textBaseline="top";
    ctx.fillStyle="#000";
    ctx.font="10px Sans-Serif";
    ctx.fillText(today,150,10);
    ctx.fillStyle="#f00";
    ctx.font="14px Sans-Serif";
    ctx.fillText(message,125,30);
    ctx.fillStyle="#109910";
    ctx.font="16px Arial";
    ctx.fillText('Guess: '+guesses,215,50);
    ctx.fillStyle="#000";
    ctx.font="16px Arial";
    ctx.fillText('Higher Or Lower: '+higherOrLower,150,125);
    ctx.fillStyle="#f00";
    ctx.font="16px Arial";
    ctx.fillText('Letters Guessed: '+lettersGuessed.toString(),10,260);
    if(gameOver){
      ctx.fillStyle="#f00";
      ctx.font="40px Arial";
      ctx.fillText("You Got It!",150,180);
    }
  }
}
<canvas id="canvas" width="500" height="300"></canvas>
<form>
  <input type="button" id="createImageData" value="Export Canvas Image" />
</form>