可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试):

问题:

the desired behavior is when the document loads, canvas draws image 0. when the invisible div is clicked, canvas draws image 1, on mouseup or mouseout, it reverts back to image 0.

I left the css out because I got that working...just need to know what I'm doing wrong with the javascript function. right now it doesn't display anything, not even the first image.

<!DOCTYPE HTML>
<html>
    <head>
        <script type="text/javascript">
        function imgChange(imagePath)
            var c=document.getElementById("myCanvas");
            var ctx=c.getContext("2d");
            var img=new Image();
            img.onload = function(){
            ctx.drawImage(img,0,0);
            };
            img.src=imagePath; <!-- I THINK THIS IS WRONG?
        </script>
    </head>

    <body>

            <canvas id="myCanvas" width="506" height="319"
onload="imgChange('0.gif')" style="border:1px solid #c3c3c3;">
            Your browser does not support the canvas element.
            </canvas>



            <div id="button1" onMouseDown="imgChange('1.gif')" onMouseUp="imgChange('0.gif')" onMouseOut="imgChange('0.gif')"></div>
            <div id="key2"></div>




    </body>

</html>

回答1:

your code is missing an ending block

function imgChange(imagePath) {
            var c=document.getElementById("myCanvas");
            var ctx=c.getContext("2d");
            var img=new Image();
            img.onload = function(){
                  ctx.drawImage(img,0,0);
            };
            img.src=imagePath;
}

The last '}' is missing