Doubts about input uploaded by H5

Why is it that when I call FileReader"s onprogressAPI to set the progress, the upload will get stuck in the middle of the upload, and then finish it directly after a while?

question code is as follows: 

     var reader = new FileReader();
     reader.onprogress = function(ev) {
         setTimeout(function(){ hr.style.width = parseInt(ev.loaded*100 / ev.total) + "%"; }, 1)
         pro.value = ev.loaded;
     }
     reader.readAsDataURL(upload.files[0]);

I want to change the progress bar according to the actual progress.

Javascript html
May.22,2021

what exactly do you mean by stuck?

whether the uploaded file is not large enough and is local, so immediately upload
try to upload a larger file from the local to the extranet server

.

Previous: FastJson custom type conversion?

Next: Webpack prompt that both webpack-cli and webpack-command are installed

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b39a49-4ee15.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b39a49-4ee15.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?