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


当前回答

我不认为你收到的警告是相关的。我有同样的警告,原来是Chrome扩展React Dev Tools。我删除了扩展,错误消失了。

其他回答

include.prepload.js文件将有如下一行,可能是最后一行:

# sourceMappingURL=include.prepload.js.map

删除它,错误就会消失。

对我来说,这些警告是由Selenium IDE Chrome扩展引起的。这些警告出现在控制台中每次页面加载:

DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/atoms.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/polyfills.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/escape.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/playback.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
DevTools failed to load source map: Could not load content for chrome-extension://mooikfkahbdckldjjndioackbalphokd/assets/record.js.map: HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME

由于Selenium IDE已经设置为能够读取所有站点上的站点数据,所以我卸载了它。(我在这里读到另一个评论,你可以尝试为一个扩展启用更多权限,而不是删除它。)在我的情况下,删除硒IDE (Chrome扩展)摆脱了警告。

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.

进入开发人员工具→设置→控制台→勾选“仅选择上下文”。警告将被隐藏。你可以通过取消同一个方框的勾选来再次看到它们。

“仅选择上下文”仅指顶部、iframe、工作上下文和扩展上下文。在绝大多数情况下,这就是你所需要的。

我很欣赏这是你的扩展的一部分,但我看到这条消息在各种各样的地方这些天,我讨厌它:我如何修复它(这个修复似乎大大加快了浏览器)是通过添加一个死文件

物理上创建它想要的文件/在它想要的位置,作为一个空白文件(例如,"popper.min.js.map") 把这个放进空白文件里 { “版本”:1、 “映射”:“”, “来源”:[], “名称”:[], “文件”:“popper.min.js” } 确保空白文件内容中的“file”:“*******”与您的文件名******相匹配。Map(去掉。Map这个词)

(我怀疑你可以自己把这个死文件方法添加到插件中。)