我试图显示从本地机器选择的图像，我需要该图像的位置用于JavaScript函数。但我查不到地址。
为了获得图像位置，我尝试使用console.log，但没有返回任何结果。
console.log(document.getElementById("uploadPreview"));
下面是HTML代码:
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<div align="center" style="padding-top: 50px">
<img align="center" id="uploadPreview" style="width: 100px; height: 100px;" />
</div>
<div align="center" style="padding-left: 30px">
<input id="uploadImage" type="file" name="myPhoto" onchange="PreviewImage();" />
</div>
<script type="text/javascript">
function PreviewImage() {
var oFReader = new FileReader();
oFReader.readAsDataURL(document.getElementById("uploadImage").files[0]);
oFReader.onload = function (oFREvent) {
document.getElementById("uploadPreview").src = oFREvent.target.result;
console.log(document.getElementById("uploadPreview").src);
};
}
</script>
</body>
</html>
控制台输出:
以下是警告:
DevTools无法加载SourceMap:无法加载内容
chrome扩展:/ / alplpnakfeabeiebipdmaenpmbgknjce / include.preload.js.map:
HTTP错误:状态代码404,net::ERR_UNKNOWN_URL_SCHEME
正确:这与你的代码无关。对于这个警告，我找到了两个有效的解决方案(不仅仅是禁用它)。为了更好地理解源映射是什么，我建议你看看这个答案，它解释了它是如何帮助你调试的:
The .map files are for JavaScript and CSS (and now TypeScript too) files that have been minified. They are called SourceMaps. When you minify a file, like the angular.js file, it takes thousands of lines of pretty code and turns it into only a few lines of ugly code. Hopefully, when you are shipping your code to production, you are using the minified code instead of the full, unminified version. When your app is in production, and has an error, the sourcemap will help take your ugly file, and will allow you to see the original version of the code. If you didn't have the sourcemap, then any error would seem cryptic at best.
First solution: apparently, Mr Heelis was the closest one: you should add the .map file and there are some tools that help you with this problem (Grunt, Gulp and Google closure for example, quoting the answer). Otherwise you can download the .map file from official sites like Bootstrap, jQuery, font-awesome, preload and so on... (maybe installing things like popper or swiper by the npm command in a random folder and copying just the .map file in your JavaScript/CSS destination folder)
Second solution (the one I used): add the source files using a CDN (content delivery network). (Here are all the advantages of using a CDN). Using content delivery network (CDN) you can simply add the CDN link, instead of the path to your folder. You can find CNDs on official websites (Bootstrap, jquery, popper, etc.) or you can easily search on some websites like Cloudflare, cdnjs, etc.
在Edge浏览器的控制台中发现大量源映射错误后，我偶然发现了这个Stack Overflow问题。(我想我很久以前就禁用了Chrome浏览器中的警告。)
对我来说，这意味着首先意识到源地图是什么;请参考Macro Mazzon的回答来理解这一点。既然这是个好主意，那么问题就在于如何打开它们。
这就像在webpack.config.js文件中添加这一行一样简单
module.exports = {
devtool: "source-map",
}
现在Edge可以检测到源映射，错误就消失了。
如果这个回答侮辱了任何人的智力，我很抱歉，但也许读到这篇文章的人会像我一样对源地图一无所知。
