file upload tips for web developers

7 Useful File Upload Tips for Web Developers

We must know that file uploading has gained importance in the latest web and mobile applications. We see file uploaders everywhere, from posting our resumes on a job site to uploading our images on social media. However, it is important to know that an incorrect file uploader may cause risks to our company.

No matter which file uploader we use, it is always important to take important measures. If you are a beginner looking for amazing file upload tips, look no further. We have got you an amazing list of file upload tips, especially when you are using an HTML file uploader. Let’s begin our journey.

What Is The Importance Of File Uploader?

Before knowing the important tips, we must realize the importance of a file uploader. We are living in an era of technology where we, as users, generate a lot of content. This content needs to be transmitted from one platform or device to another platform or device. File uploader works as a bridge between two or more devices or platforms to transmit the data.

File uploaders help us to increase user productivity as well as business performance. Some most common examples that use file uploaders are messaging applications, insurance sites, healthcare portals, and content management systems. Let’s check out some amazing tips for using a file uploader.

What Are The Best Tips That Developers Should Follow For File Upload?

File uploaders, if not correctly implemented, may cause a significant risk to our business’s performance. Here are the 7 best tips web developers should follow to implement a file uploader correctly.

1. Virus Scanning On Server Side

For the safety of our application, we must ensure that the user-generated content on our site has no virus. Therefore, it is important to perform virus scanning of content that users upload on an application or website. It will help us ensure the uploading of safe and secure content.

The best advantage of this practice is that it ensures the smooth running of your computer and prevents potential security threats.

2. Single & Multiple File Uploads

We can implement the file uploader functionality into our app by using the input type as <file>. It will allow the user to upload files. However, it allows the uploading of a single file uploader by default.

<pre class=”lang:json aphph-pretag-focused”>


<input type=”file” id=”file-uploader”/>


When uploading multiple files, we need to add <multiple> into our code line.

<pre class=”lang:json aphph-pretag-focused”>

<input type=”file” id=”file-uploader” multiple />


3. File Metadata

Knowing the metadata of our file can help us in an effective decision-making process. We must know the fact that the <file> object contains important information about the metadata of our file. This metadata includes information like file size, name, type, last update, etc.

<pre class=”lang:json aphph-pretag-focused”>

// Get the file uploader by id

const fileUploader = document.getElementById(‘file-uploader’);


// Listen to the change event and read metadata

fileUploader.addEventListener(‘change’, (event) => {

  // Get the FileList array

  const files =;


  // Loop through the files and get metadata

  for (const file of files) {

    const name =;

    const type = file.type ? file.type: ‘NA’;

    const size = file.size;

    const lastModified = file.lastModified;

    console.log({ file, name, type, size, lastModified });




4. Know About The File <accept> Property

It is interesting to know that the <accept> attribute helps us limit the file types on our web app. This is how we can allow only some types of files to browse when the user wants to upload files. The code line given below can be helpful.

<pre class=”lang:json aphph-pretag-focused”>

<input type=”file” id=”file-uploader” accept=”.jpg, .png” multiple>



The above code line only allows the uploading of jpg and png files.

5. Management of File Content & Check for Malicious Content

Once we upload our file, we may need to review the file content. It can help us to manage the file content and remove the malicious content, if any. However, when it comes to uploading the profile picture, it can be confusing if we do not want to show the picture to users. In such a case, the <FileReader> object helps us to convert the file into a binary string.

<pre class=”lang:json aphph-pretag-focused”>

// Get the instance of the FileReader

const reader = new FileReader();


fileUploader.addEventListener(‘change’, (event) => {

  const files =;

  const file = files[0];


  // Get the file object after upload and read the

  // data as URL binary string



  // Once loaded, do something with the string

  reader.addEventListener(‘load’, (event) => {

    // Here we are creating an image tag and adding

    // an image to it.

    const img = document.createElement(‘img’);


    img.src =;

    img.alt =;




6. Restriction of File Size

As we know, when the user uploads any file size or type, it can impose a security risk on our application. Therefore, it is important to restrict the file size as well. Moreover, the uploading of large file sizes can also affect the performance of our application. Limiting the file sizes on our web application is important to prevent these problems.

7. Showing the File Upload Progress

The best practice for file uploading is to let users know about the progress of the file upload. We can implement it with the help of a progress bar. We must know that implementing <progress> event into <FileReader> can show a progress bar. Here is an example of code:

<pre class=”lang:json aphph-pretag-focused”>

reader.addEventListener(‘progress’, (event) => {

  if (event.loaded && {

    // Calculate the percentage completed

    const percent = (event.loaded / * 100;

    // Set the value to the progress component

    progress.value = percent;






File uploaders play an important role in the success of different web and mobile applications. However, the tips above can make it more successful. Note that keeping our software up to date is also a tip to increase the performance of file uploaders. At the same time, implementing HTTPS can allow safe data transmission between client and server.


What Is an Uploader on YOUTUBE?

Youtube uses the package uploader that allows us to quickly upload sound recordings, videos, and other metadata in bulk amounts.

What Is an Image Uploader?

The image uploader is designed to help you with mass file uploading on your web or mobile applications.

What Is the Uploading Process?

Uploading refers to a process in which we transmit data from our device to another device using a specific network. It can also be transmitted from one platform to another.

What Is the Best File Uploader?

The best file uploader depends on our requirements and resources. However, Filestack, Uppy, Filepond, and Uploadcare are some most common examples.

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