Save HTML form data

You can submit forms to Val Town using the HTTP handler Val . You can place these forms on any page on the internet - or host the form directly on Val Town.

These examples show how to accept and store email addresses on Val Town. The email addresses are saved into a val, and you also get sent an email notification for each new signup.

Add a form to your website

Create a val that uses the HTTP handler Val

Write a val function that accepts a Request and returns a Response.

import { blob } from "https://esm.town/v/std/blob?v=11";
import { email } from "https://esm.town/v/std/email?v=11";

export const saveFormData = async (req: Request) => {
  // Get existing list of submitted email addresses
  let submittedEmailAddresses = await blob.getJSON("submittedEmailAddresses") as string[];

  // If there were no email addresses stored, create an empty array
  submittedEmailAddresses ??= [];

  // Pick out the form data
  const formData = await req.formData();
  const emailAddress = formData.get("email") as string;
  if (submittedEmailAddresses.includes(emailAddress)) {
    return new Response("You're already signed up!");
  }

  // Send a notification email
  email({ text: `${emailAddress} just signed up!`, subject: "New sign up" });

  // Store form data
  submittedEmailAddresses.push(emailAddress);
  await blob.setJSON("submittedEmailAddresses", submittedEmailAddresses);

  return new Response("Thanks! You're signed up!");
};

Add the form to your webpage

Copy your val’s Web endpoint URL using the menu (Endpoints > Copy web endpoint) and set it as the form’s action (this tells the form where to send its data when it’s submitted).

Below is a full HTML page example. If you are adding a form to an existing page just copy and paste the <form></form> block.

<!DOCTYPE html>
<html>
  <head>
    <title>Email Form</title>
  </head>
  <body>
    <!-- Change the action here to your val's Express endpoint! -->
    <form action="https://user-saveFormData.web.val.run" method="post">
      <label for="email">Email:</label>
      <input type="email" id="email" name="email" required />
      <br />
      <input type="submit" value="Submit" />
    </form>
  </body>
</html>

Host your form on Val Town

There are two ways to do this. You can write a val function that serves a webpage, and a separate val that accepts the form data - or you can write a single val that does both like the example below.

When a form is submitted, it sends a HTTP request with the POST method. When a user visits a webpage in their web browser, the server (your val function) gets sent a GET request.

You can check the HTTP method using req.method and change how your val function responds.

import { blob } from "https://esm.town/v/std/blob?v=11";
import { email } from "https://esm.town/v/std/email?v=11";
import { thisWebURL } from "https://esm.town/v/stevekrouse/thisWebURL?v=2";

export const renderFormAndSaveData = async (req: Request) => {
  // A visit from a web browser? Serve a HTML page with a form
  if (req.method === "GET") {
    return new Response(
      `
<!DOCTYPE html>
<html>
<head>
  <title>Email Form</title>
</head>
<body>
  <form action="${thisWebURL()}" method="post">
    <label for="email">Email:</label>
    <input type="email" id="email" name="email" required>
    <br>
    <input type="submit" value="Submit">
  </form>
</body>
</html>
    `,
      { headers: { "Content-Type": "text/html" } },
    );
  }

  // Get existing list of submitted email addresses
  let submittedEmailAddresses = await blob.getJSON("submittedEmailAddresses") as string[];

  // If there were no email addresses stored, create an empty array
  submittedEmailAddresses ??= [];

  // Pick out the form data
  const formData = await req.formData();
  const emailAddress = formData.get("email") as string;
  if (submittedEmailAddresses.includes(emailAddress)) {
    return new Response("You're already signed up!");
  }
  email({ text: `${emailAddress} just signed up!`, subject: "New sign up" });
  // Store form data
  submittedEmailAddresses.push(emailAddress);
  await blob.setJSON("submittedEmailAddresses", submittedEmailAddresses);

  return new Response("Thanks! You're signed up!");
};

See Web forms — Working with user data on the MDN Web Docs site for more help with forms. Forms are a basic part of the web - you don’t need a lot of front-end JavaScript to make them work.