admin管理员组

文章数量:1328376

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>

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>
  • javascript
  • html
  • canvas
  • html5-canvas
Share asked May 26, 2012 at 2:48 3z33etm3z33etm 1,1134 gold badges16 silver badges26 bronze badges
Add a ment  | 

2 Answers 2

Reset to default 3

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

JavaScript looks good. But you can't click on an invisible div. Make the div visible and try.

Be aware of same origin policy too. Image path should be in your domain. If you are running in localhost you might need to have a local HTTP server.

本文标签： htmlchange canvas image with javascriptStack Overflow

版权声明：本文标题：html - change canvas image with javascript - Stack Overflow 内容由网友自发贡献，该文观点仅代表作者本人， 转载请联系作者并注明出处：http://www.betaflare.com/web/1742232070a2437401.html， 本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌抄袭侵权/违法违规的内容，一经查实，本站将立刻删除。