Express.js Forms and Validation

Handling forms and validating user input are common tasks in web applications. Express.js makes it easy to manage forms and perform validation. This guide covers key concepts, examples, and best practices for handling forms and validation in Express.js.

Key Concepts of Forms and Validation

Form Handling: Processing form data submitted by users.
Validation: Checking user input for correctness and completeness.
Sanitization: Cleaning user input to remove or escape harmful characters.
Middleware: Functions that handle validation and sanitization in the request-response cycle.

Handling Forms in Express.js

Use the express.urlencoded middleware to parse URL-encoded form data and express.json for JSON data:

Example: Handling Form Data

// form.js
const express = require('express');
const app = express();
const port = 3000;

// Parse URL-encoded form data
app.use(express.urlencoded({ extended: true }));

// Parse JSON data
app.use(express.json());

app.post('/submit', (req, res) => {
    res.send(`Form Submitted: ${req.body.name}`);
});

app.listen(port, () => {
    console.log(`Server running at http://localhost:${port}/`);
});

Setting Up a Basic Form

Create a simple HTML form and handle form submissions:

Example: Basic HTML Form





    Form Example


    
        Name: