我的代码是这样的

    <html>
  <head>
  </head>
  <body>
    <canvas id="myCanvas" width="578" height="200" style="display:none;"></canvas>
    <img id="canvasImg" onclick="myFunction()" alt="Right click to save me!">
    <script>
        var canvas = document.getElementById('myCanvas');
        var context = canvas.getContext('2d');
        function myFunction() {
            var c = document.getElementsByTagName("canvas");
            // save canvas image as data url (png format by default)
            var dataURL = c.toDataURL();
            // set canvasImg image src to dataURL
            // so it can be saved as an image
            document.getElementById('canvasImg').src = dataURL;
        }
    </script>
  </body>
</html>


当我点击canvasImg时抛出错误

Uncaught TypeError: Object #<NodeList> has no method 'toDataURL'


我做了一个fiddle here
谁能指出出什么问题了?

最佳答案

DEMO

document.getElementsByTagName返回元素对象的数组,并且没有数组对象具有toDataUrl方法

代替这个

var c = document.getElementsByTagName("canvas");




 var c = document.getElementsByTagName("canvas")[0];

10-05 21:06
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