Javascript错误：第一行的输入意外结束，没有任何明显的问题，但是我收到一条消息，整个画布停止了

Question

I put in the entire thing just in case I went into chrome and looked for errors, and it wasnt working either so I checked, apparently the first line has a problem. I kept the first 6 lines and deleted all else then it worked fine, so I went to SublimeText2 and searched for every ) and } in the code.

var canvasBg = document.getElementById('canvasBg');
var ctxBg = canvasBg.getContext('2d');


var canvasJet = document.getElementById('canvasJet');
var ctxJet = canvasJet.getContext('2d');

var jet1;
var fps = 17;
var drawInterval;

var imgSprite = new Image();
imgSprite.src = 'SpriteSheet.png'
imgSprite.addEventListener('load',init,false);


function init() {
    drawBg();
    startDrawing();
    jet1 = new Jet();
    document.addEventListener('keydown',checkKeyDown,false);
    document.addEventListener('keyup',checKeyUp,false);
}

function draw() {
    jet1.draw();
}


function startDrawing() {
    stopDrawing();
    drawInterval = setInterval(draw,fps);
}


function stopDrawing() {
    clearInterval(setInterval);
}



Jet.prototype.draw = function() {
    clearCtxJet();
    ctxJet.drawImage(imgSprite,this.srcX,this.srcY,this.width,this.height,this.drawX,this.drawY,this.width,this.height);

};




function Jet() {
    this.srcX = 0;
    this.srcY = 0;
    this.drawX = 200;
    this.drawY = 200;
    this.width = 96;
    this.height = 30;
    }



function drawJet() {
}





function drawBg() {

    ctxBg.drawImage(imgSprite,96,0,800,500,0,0,800,500)

}

function clearCtxBg() {
    ctxBg.clearRect(0,0,800,500);
}

function clearCtxJet() {
    ctxJet.clearRect(0,0,800,500);
}



function checkKeyDown(e) {

    var keyID = (e.keyCode) ? e.keyCode : e.which;
    if (keyID === 38) { // 38 is up key
        alert('up arrow was pressed');
        e.preventDeafault();
    }

    if (keyID === 39) { // 39 is right key
        e.preventDeafault();
    }

    if (keyID === 40) { // 40 is down key
        e.preventDeafault();
    }

    if (keyID === 37) { // 37 is left key
        e.preventDeafault();
    }


function checkKeyup(e) {

    var keyID = (e.keyCode) ? e.keyCode : e.which;
    if (keyID === 38) { // 38 is up key
        alert('up arrow was pressed');
        e.preventDeafault();
    }

    if (keyID === 39) { // 39 is right key
        e.preventDeafault();
    }

    if (keyID === 40) { // 40 is down key
        e.preventDeafault();
    }

    if (keyID === 37) { // 37 is left key
        e.preventDeafault();
    }

}

Answer 1

I assume you're showing only parts of the code so there's no way of knowing whether this is the actual error, but both checkKeyup and checkKeydown are missing closing braces.

I recommend installing Package Control for Sublime Text 2 and then using it to install SublimeLinter which will be able to check your code for you and point out missing semicolons and braces.

Answer 2

看到http://jsfiddle.net的完整代码将非常高兴