案例：html/html5 案例     状态：可编辑再运行    进入竖版
 运行结果　
​x
 
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<!DOCTYPE html>
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<html>
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<body>
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​
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<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;">
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Your browser does not support the HTML5 canvas tag.
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</canvas>
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​
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<script>
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​
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var c=document.getElementById("myCanvas");
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var ctx=c.getContext("2d");
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var imgData=ctx.createImageData(100,100);
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alert("Width of imgData is: " + imgData.width);
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for (var i=0;i<imgData.data.length;i+=4)
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  {
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  imgData.data[i+0]=255;
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  imgData.data[i+1]=0;
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  imgData.data[i+2]=0;
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  imgData.data[i+3]=255;
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  }
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ctx.putImageData(imgData,10,10);
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​
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</script>
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​
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</body>
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</html>
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​