javascript在画布上上传图像
[英]javascript upload an image in canvas
问题描述
I try to upload and draw an image into a canvas. 
我尝试上传图像并将其绘制到画布中。 I have the html code for button and canvas and js code for onchange event. 我有用于按钮和画布的html代码以及用于onchange事件的js代码。 My code does not work and I do not have any errors to figure out what is going on. 我的代码不起作用，并且我没有任何错误可以弄清楚发生了什么。
1 个解决方案
解决方案1
1 已采纳 2018-01-03 15:48:11
The fix is by simply including your scripts at the end of the body before the closing tag </body> . 解决方法是简单地在结束标记</body>之前的正文末尾包含脚本 。
Your html code will appear like this: 您的html代码将如下所示：
<html>
<body>
<div id="buttonsDiv" >
<input type="file" accept="image/*" title="Upload Image" class="normal-button" id="uploadBtn"/>
</div>
<canvas id= "myImgCanvas" title="Drop an image here to upload" ></canvas>
<script src="myFileName.js"></script>
</body>
</html>
Note that you must pay attention when you should/ should not include your scripts in the <head> tag vs including it at the end of the </body> tag. 请注意，在应该/不应该将脚本包括在<head>标记中而不是在</body>标记的末尾包含脚本时，您必须注意。 You can check this post for the best practice. 您可以查看此帖子以获得最佳实践。
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