WebThe FileReader.onload property contains an event handler executed when the FileReader.load_event event is fired, when content read with readAsArrayBuffer, readAsBinaryString, readAsDataURL or readAsText is available. Web文件上传现在都是很常见的了，可以上传文件，上传头像等，不同的浏览器“文件上传”有不同的效果 先看下火狐浏览器的效果是这样的： 再看下ie浏览器是这样的： 还有很多其他的浏览器，就不一一的查看效果了，那么这个上传是怎么实现的呢？
Using the FileReader API to preview images in React
http://duoduokou.com/html/50817063656423741531.html WebApr 7, 2024 · FileReader.readAsDataURL () The readAsDataURL method is used to read the contents of the specified Blob or File. When the read operation is finished, the readyState becomes DONE, and the loadend is triggered. At that time, the result attribute contains the data as a data: URL representing the file's data as a base64 encoded string. mattress firm chester
TypeScript: BlobをDataURLに変換する6行の関数 - Qiita
WebBegins reading from blob as a string. The result will be stored on this.result after the 'load' event fires. For the valid values of encoding, see character sets.See also Blob.text(). Web使用性能開發工具在 Chrome 中進行的分析顯示，在reader.onloadend之前有大量空閑時間，並且 ram 使用量沒有增加。 然而，這可能是因為FileApi是在瀏覽器本身中實現的，並且不會反映在 JavaScript 性能統計數據中。 我對 FileReader 的實現看起來像這樣： WebJun 9, 2024 · Now we can start working on the upload_file () function that will do most of the heavy lifting. First we grab a chunk of the selected file using the JavaScript slice () method: function upload_file( start ) { var next_slice = start + slice_size + 1 ; var blob = file.slice ( start, next_slice ); } We’ll also need to add a function within the ... mattress firm centerville ohio