How to Build a Web App on Blogspot Using HTML Embedding and IndexedDB

IndexedDB Note App

📝 Simple Note App (IndexedDB)

1. Introduction

In this tutorial, we will learn how to turn a Blogspot page into a simple web app by:

Embedding HTML and JavaScript directly into a blog post
Using IndexedDB to store data locally in the browser (no backend required)

We will build a simple example: a Note-Taking Web App.

2. What is IndexedDB?

IndexedDB is a built-in browser database that allows you to store structured data locally.

Key features:

Stores large amounts of data
Supports object-based storage (like JSON)
Works offline
More powerful than localStorage

Common use cases:

Note apps
Todo lists
Offline web applications

3. How to Embed a Web App in Blogspot

To run a web app inside Blogspot:

Go to New Post
Switch to HTML view
Paste your full HTML + JavaScript code into the editor

4. Example Web App (Note App using IndexedDB)

You can copy and paste this directly into a Blogspot post:


<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>IndexedDB Note App</title>
  <style>
    body { font-family: Arial; padding: 20px; }
    input, button { padding: 10px; margin: 5px; }
    .note { padding: 10px; border: 1px solid #ccc; margin-top: 5px; }
  </style>
</head>
<body>

<h2>📝 Simple Note App (IndexedDB)</h2>

<input id="noteInput" placeholder="Write a note...">
<button onclick="addNote()">Add</button>

<div id="list"></div>

<script>
let db;

// Open database
const request = indexedDB.open("NoteDB", 1);

request.onupgradeneeded = function(e) {
  db = e.target.result;
  db.createObjectStore("notes", { keyPath: "id", autoIncrement: true });
};

request.onsuccess = function(e) {
  db = e.target.result;
  loadNotes();
};

// Add note
function addNote() {
  const text = document.getElementById("noteInput").value;
  if (!text) return;

  const tx = db.transaction("notes", "readwrite");
  const store = tx.objectStore("notes");

  store.add({ text: text });

  tx.oncomplete = () => {
    document.getElementById("noteInput").value = "";
    loadNotes();
  };
}

// Load notes
function loadNotes() {
  const list = document.getElementById("list");
  list.innerHTML = "";

  const tx = db.transaction("notes", "readonly");
  const store = tx.objectStore("notes");

  store.openCursor().onsuccess = function(e) {
    const cursor = e.target.result;
    if (cursor) {
      const div = document.createElement("div");
      div.className = "note";
      div.innerHTML = cursor.value.text;
      list.appendChild(div);
      cursor.continue();
    }
  };
}
</script>

</body>
</html>