Validate Image on Drop in JavaScript Uploader control

30 Mar 2023 / 2 minutes to read

The uploader component allows you to upload all type of images by setting *image/ ** to allowedExtensions property.

By default, the behavior is working with select a file using browse button. But, this behavior doesn’t support on drag and drop the files. You can handle this behavior manually using selected event by filtering the file types from application.

In the following example, validated image files using images/*. You are able to drag and drop the image files with extension of PNG, JPG, BPG, GIF and TIFF to upload it.

Source

Preview

app.ts

index.html

index.css

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


let uploadObj: any = new Uploader({
    asyncSettings: {
        saveUrl: 'https://ej2.syncfusion.com/services/api/uploadbox/Save',
        removeUrl: 'https://ej2.syncfusion.com/services/api/uploadbox/Remove'
    },
    autoUpload: false,
    allowedExtensions: 'image/*',
    selected: onSelect

});
uploadObj.appendTo('#fileupload');

function onSelect(args: any): void {
  if (args.event.type === 'drop') {
    let allImages: Array<string> = ['png', 'jpg', 'jpeg', 'gif', 'tiff', 'bpg'];
    let files = args.filesData;
    let modifiedFiles = [];
    for (let file of files) {
      if (allImages.indexOf(file.type) === -1) {
        file.status = 'File type is not allowed';
        file.statusCode = '0';
      }
      modifiedFiles.push(file);
    }
    args.isModified = true;
    args.modifiedFilesData = modifiedFiles.concat(uploadObj.filesData);
  }
}

<!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.