How can I get a file's upload size using simple Javascript?

Question

I have upload file functionality on one of the page. I check for the extension of the file using JavaScript. Now i want to restrict the user from uploading file greater than

Answer 1

Now it is possible to get file size using pure JavaScript. Nearly all browser support FileReader, which you can use to read file size as well as you can show image without uploading file to server. link

Code:

    var oFile = document.getElementById("file-input").files[0]; // input box with type file;
    var img = document.getElementById("imgtag");
    var reader = new FileReader();
    reader.onload = function (e) {
            console.log(e.total); // file size 
            img.src =  e.target.result; // putting file in dom without server upload.

   };
   reader.readAsDataURL(oFile );

You can get file size directly from file object using following code.

 var fileSize = oFile.size;