[javascript] getting file size in javascript

given a path of a file like:
C:\file.jpg
how can i get the size of the file in javascript?

function findSize() {
    var fileInput =  document.getElementById("fUpload");
    try{
        alert(fileInput.files[0].size); // Size returned in bytes.
    }catch(e){
        var objFSO = new ActiveXObject("Scripting.FileSystemObject");
        var e = objFSO.getFile( fileInput.value);
        var fileSize = e.size;
        alert(fileSize);    
    }
}

You cannot.

JavaScript cannot access files on the local computer for security reasons, even to check their size.

The only thing you can do is use JavaScript to submit the form with the file field to a server-side script, which can then measure its size and return it.

If you could access the file system of a user with javascript, image the bad that could happen.

However, you can use File System Object but this will work only in IE:

http://bytes.com/topic/javascript/answers/460516-check-file-size-javascript

You can't get the file size of local files with javascript in a standard way using a web browser.

But if the file is accessible from a remote path, you might be able to send a HEAD request using Javascript, and read the Content-length header, depending on the webserver

To get the file size of pages on the web I built a javascript bookmarklet to do the trick. It alerts the size in kb's. Change the alert to a prompt if you want to copy the filesize.

Here's the bookmarklet code for the alert.

<a href="javascript:a=document.getElementsByTagName('HTML')[0].outerHTML;b=a.length/1024;c=Math.round(b);alert(c+' kb');">Doc Size</a>

Here's the bookmarklet code for the prompt.

<a href="javascript:a=document.getElementsByTagName('HTML')[0].outerHTML;b=a.length/1024;c=Math.round(b);prompt('Page Size',c+' kb');">Doc Size</a>

See it in action at http://bookmarklets.to.g0.to/filesize.php

You could probably try this to get file sizes in kB and MB Until the file size in bytes would be upto 7 digits, the outcome would be in kbs. 7 seems to be the magic number here. After which, if the bytes would have 7 to 10 digits, we would have to divide it by 10**3(n) where n is the appending action . This pattern would repeat for every 3 digits added.

let fileSize = myInp.files[0].size.toString();

if(fileSize.length < 7) return `${Math.round(+fileSize/1024).toFixed(2)}kb`
    return `${(Math.round(+fileSize/1024)/1000).toFixed(2)}MB`

You cannot as there is no file input/output in Javascript. See here for a similar question posted.

Try this one.

function showFileSize() {_x000D_
  let file = document.getElementById("file").files[0];_x000D_
  if(file) {_x000D_
    alert(file.size + " in bytes"); _x000D_
  } else { _x000D_
    alert("select a file... duh"); _x000D_
  }_x000D_
}

<input type="file" id="file"/>_x000D_
<button onclick="showFileSize()">show file size</button>