Check File Size before Uploading in JavaScript Uploader control

23 Mar 2023 / 1 minute to read

By using the uploading event, you can get the file size before uploading it to the server. File object contains the file size in bytes only. You can convert the size to standard formats (KB or MB) using bytesToSize method.

Source

Preview

app.ts

index.html

index.css

import { Uploader } from '@syncfusion/ej2-inputs';

//Initialize the control by preload files
let uploadObj: Uploader = new Uploader({
    autoUpload: false,
    asyncSettings: {
        saveUrl: 'https://ej2.syncfusion.com/services/api/uploadbox/Save',
        removeUrl: 'https://ej2.syncfusion.com/services/api/uploadbox/Remove'
    },
    uploading: onBeforeUpload
});
uploadObj.appendTo('#fileupload');

function onBeforeUpload(args): void {
    // get the file size in bytes
    let sizeInBytes: number = args.fileData.size;
    // get the file size in standard format
    alert("File size is: " + uploadObj.bytesToSize(sizeInBytes));
}

<!DOCTYPE html>
<html lang="en">

<head>
            
    <title>Essential JS 2 Uploader</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Essential JS 2 Uploader Component" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/21.1.35/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/21.1.35/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/21.1.35/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/21.1.35/ej2-buttons/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
        <div id='container'>
            <input type="file" id="fileupload" name="UploadFiles"/>
        </div>
    </div>
</body>
</html>

#container {
  visibility: hidden;
}

#loader {
  color: #008cff;
  font-family: 'Helvetica Neue','calibiri';
  font-size: 14px;
  height: 40px;
  left: 45%;
  position: absolute;
  top: 45%;
  width: 30%;
}

You can also explore JavaScript File Upload feature tour page for its groundbreaking features. You can also explore our JavaScript File Upload example to understand how to browse the files which you want to upload to the server.