devdunia/base64-decoder.html at main · echobash/devdunia · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Base64 Decoder — DevDunia</title>
<meta name="description" content="Decode Base64 encoded data back to original format. Free online Base64 decoder tool for developers.">
<meta property="og:type" content="website">
<meta property="og:url" content="https://devdunia.com/base64-decoder.html">
<meta property="og:title" content="Base64 Decoder — DevDunia">
<meta property="og:description" content="Decode Base64 encoded data back to original format. Free online Base64 decoder tool.">
<meta property="og:image" content="https://devdunia.com/images/logo.png">
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="stylesheet" href="css/comic.css">
<link href="https://fonts.googleapis.com/css2?family=Bangers&family=Comic+Neue:wght@400;700&family=Space+Mono:wght@400;700&display=swap" rel="stylesheet">
<style>
/* ---- TODO migrate: page-specific overrides, not yet centralized in css/comic.css ---- */
.hero-text h1 {
  font-family: 'Bangers', cursive;
  font-size: 2.8rem;
  letter-spacing: 2px;
  color: var(--blue);
  -webkit-text-stroke: 1px var(--ink);
  text-shadow: 4px 4px 0 var(--ink);
  line-height: 1;
  text-transform: uppercase;
}
.comic-textarea:focus { border-color: var(--blue); box-shadow: inset 3px 3px 0 rgba(29,111,184,.1); }

.btn-primary { background: var(--blue);   color: #fff; }
.btn-purple  { background: var(--purple); color: #fff; }

/* ── SUCCESS BUBBLE ── */
.success-bubble {
  display: none;
  position: relative;
  background: #f0fff4;
  border: 3px solid var(--green);
  border-radius: 14px;
  padding: 10px 14px;
  margin-top: 12px;
  font-size: .88rem;
  color: var(--ink);
}
.success-bubble.show { display: block; }

/* ── STATS ROW ── */
.stats-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}
.stat-chip.chip-blue   { background: var(--blue);   color: #fff; }
.stat-chip.chip-green  { background: var(--green);  color: #fff; }
.stat-chip.chip-purple { background: var(--purple); color: #fff; }
.stat-chip.chip-yellow { background: var(--yellow); color: var(--ink); }

/* ── EXAMPLES GRID ── */
.examples-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.example-card {
  background: var(--paper2);
  border: 3px solid var(--ink);
  border-radius: 6px;
  box-shadow: 4px 4px 0 var(--ink);
  padding: 10px 12px;
  cursor: pointer;
  transition: transform .1s, box-shadow .1s;
}
.example-card:hover { transform: translate(-2px,-2px); box-shadow: 6px 6px 0 var(--ink); }
.example-card:active { transform: translate(1px,1px); box-shadow: 2px 2px 0 var(--ink); }

.example-title {
  font-family: 'Bangers', cursive;
  font-size: 1rem;
  letter-spacing: 1px;
  margin-bottom: 4px;
}

.example-encoded {
  font-family: 'Space Mono', monospace;
  font-size: .68rem;
  color: var(--blue);
  word-break: break-all;
  margin-bottom: 2px;
}

.example-arrow {
  font-size: .75rem;
  color: var(--ink);
  opacity: .55;
}

/* ── DIVIDER ── */
.divider {
  border: none;
  border-top: 3px solid var(--ink);
  margin: 16px 0;
}

/* ── MOBILE ── */
@media (max-width: 600px) {
  .examples-grid { grid-template-columns: 1fr; }
  .hero { flex-direction: column; gap: 10px; }
  .hero-text h1 { font-size: 2rem; }
  .stats-row { gap: 6px; }
}
</style>
</head>
<body>
<div class="paper-overlay"></div>
<div data-masthead></div>

<div class="page-wrap">

  <div data-tool-hero
     data-title="Base64 Decoder"
     data-chapter="05"
     data-category="Encoders & Decoders"
     data-icon="&#x1F513;"
     data-desc="Paste any Base64-encoded string and crack it open instantly. No server, no tracking — pure client-side decoding right in your browser!"
     data-color="green"
     data-badges="CLIENT-SIDE,NO SERVER,FREE,INSTANT"
     data-badge-colors="blue,green,yellow,red">
  </div>

  <!-- MASTHEAD -->

  <!-- HERO -->


  <!-- INPUT PANEL -->
  <div class="panel">
    <div class="panel-header">
      &#x1F4E5; PASTE YOUR BASE64 HERE
      <span class="panel-tag">INPUT</span>
    </div>
    <div class="panel-body">
      <div class="section-label">Base64 Encoded Data</div>
      <textarea id="base64-input" class="comic-textarea" rows="6"
        placeholder="Paste Base64 encoded data here... e.g. SGVsbG8gV29ybGQ="></textarea>

      <div class="btn-row">
        <button id="decode-btn" class="btn btn-primary">&#x26A1; Decode!</button>
        <button id="encode-btn" class="btn btn-neutral">&#x1F504; Encode Instead</button>
        <button id="clear-btn" class="btn btn-danger">&#x1F5D1; Clear</button>
      </div>

      <div id="error-bubble" class="error-bubble">
        &#x1F4A5; <span id="error-msg">Invalid Base64!</span>
      </div>
    </div>
  </div>

  <!-- OUTPUT PANEL -->
  <div class="panel" id="output-panel" style="display:none;">
    <div class="panel-header">
      &#x1F4E4; DECODED OUTPUT
      <span class="panel-tag">OUTPUT</span>
    </div>
    <div class="panel-body">
      <div class="section-label">Decoded Text</div>
      <div class="output-wrap">
        <textarea id="base64-output" class="comic-textarea" rows="7" readonly></textarea>
        <button id="copy-btn" class="copy-btn">&#x1F4CB; COPY</button>
      </div>

      <!-- STATS -->
      <div class="stats-row" id="stats-row">
        <div class="stat-chip chip-blue">
          <span class="stat-label">B64 SIZE</span>
          <span id="stat-b64-size">—</span>
        </div>
        <div class="stat-chip chip-green">
          <span class="stat-label">DECODED</span>
          <span id="stat-dec-size">—</span>
        </div>
        <div class="stat-chip chip-purple">
          <span class="stat-label">OVERHEAD</span>
          <span id="stat-overhead">—</span>
        </div>
        <div class="stat-chip chip-yellow">
          <span class="stat-label">PADDING</span>
          <span id="stat-padding">—</span>
        </div>
      </div>
    </div>
  </div>

  <!-- EXAMPLES PANEL -->
  <div class="panel">
    <div class="panel-header">
      &#x1F4DA; TRY AN EXAMPLE — CLICK TO LOAD!
      <span class="panel-tag">EXAMPLES</span>
    </div>
    <div class="panel-body">
      <div class="examples-grid">
        <div class="example-card" data-encoded="SGVsbG8gV29ybGQ=">
          <div class="example-title" style="color:var(--blue);">Simple Text</div>
          <div class="example-encoded">SGVsbG8gV29ybGQ=</div>
          <div class="example-arrow">&#x2193; "Hello World"</div>
        </div>
        <div class="example-card" data-encoded="eyJuYW1lIjoiQWxpIiwidG9vbCI6IkRldk51bmlhIn0=">
          <div class="example-title" style="color:var(--green);">JSON Object</div>
          <div class="example-encoded">eyJuYW1lIjoiQWxpIiwidG9vbCI6IkRldk51bmlhIn0=</div>
          <div class="example-arrow">&#x2193; {"name":"Ali",...}</div>
        </div>
        <div class="example-card" data-encoded="aHR0cHM6Ly9kZXZkdW5pYS5jb20=">
          <div class="example-title" style="color:var(--purple);">URL</div>
          <div class="example-encoded">aHR0cHM6Ly9kZXZkdW5pYS5jb20=</div>
          <div class="example-arrow">&#x2193; https://devdunia.com</div>
        </div>
        <div class="example-card" data-encoded="U2VjcmV0TWVzc2FnZTEyMw==">
          <div class="example-title" style="color:var(--red);">Hidden Message</div>
          <div class="example-encoded">U2VjcmV0TWVzc2FnZTEyMw==</div>
          <div class="example-arrow">&#x2193; SecretMessage123</div>
        </div>
      </div>
    </div>
  </div>

  <!-- HOW IT WORKS -->
  <div class="panel">
    <div class="panel-header">
      &#x1F9E0; HOW BASE64 WORKS
      <span class="panel-tag">EXPLAINER</span>
    </div>
    <div class="panel-body">
      <div class="how-steps">
        <div class="how-step">
          <div class="step-dot" style="background:var(--blue);">1</div>
          <p>Every character in your text becomes its <strong>ASCII number</strong> (e.g. 'H' → 72, 'i' → 105).</p>
        </div>
        <div class="how-step">
          <div class="step-dot" style="background:var(--green);">2</div>
          <p>Those bytes are grouped into <strong>3-byte chunks</strong> (24 bits) then split into <strong>four 6-bit groups</strong>.</p>
        </div>
        <div class="how-step">
          <div class="step-dot" style="background:var(--orange);">3</div>
          <p>Each 6-bit value maps to one of <strong>64 characters</strong>: A-Z, a-z, 0-9, +, /. That's where the name comes from!</p>
        </div>
        <div class="how-step">
          <div class="step-dot" style="background:var(--purple);">4</div>
          <p><code>=</code> padding is added to make the output length a multiple of 4. This decoder strips it automatically.</p>
        </div>
        <div class="how-step">
          <div class="step-dot" style="background:var(--red);">5</div>
          <p>Decoding is the exact reverse — Base64 chars → 6-bit groups → bytes → original text. <strong>~33% size overhead</strong> is the trade-off for safe ASCII transport.</p>
        </div>
      </div>
    </div>
  </div>

</div><!-- /page-wrap -->

<script>
(function() {
  var inputEl   = document.getElementById('base64-input');
  var outputEl  = document.getElementById('base64-output');
  var decodeBtn = document.getElementById('decode-btn');
  var encodeBtn = document.getElementById('encode-btn');
  var clearBtn  = document.getElementById('clear-btn');
  var copyBtn   = document.getElementById('copy-btn');
  var outPanel  = document.getElementById('output-panel');
  var errBubble = document.getElementById('error-bubble');
  var errMsg    = document.getElementById('error-msg');

  var statB64   = document.getElementById('stat-b64-size');
  var statDec   = document.getElementById('stat-dec-size');
  var statOver  = document.getElementById('stat-overhead');
  var statPad   = document.getElementById('stat-padding');

  var encodeMode = false;

  function showError(msg) {
    errMsg.textContent = msg;
    errBubble.classList.add('show');
  }
  function hideError() { errBubble.classList.remove('show'); }

  function showOutput(text) {
    outputEl.value = text;
    outPanel.style.display = 'block';
    hideError();
  }

  function formatBytes(n) {
    if (n === 0) return '0 B';
    if (n < 1024) return n + ' B';
    return (n / 1024).toFixed(1) + ' KB';
  }

  function isValidBase64(str) {
    try { return btoa(atob(str)) === str; } catch(e) { return false; }
  }

  function decode() {
    var raw = inputEl.value.trim();
    if (!raw) { showError('Please paste some Base64 data first!'); return; }
    var clean = raw.replace(/\s/g, '');
    if (!isValidBase64(clean)) { showError('That does not look like valid Base64. Check for typos!'); outPanel.style.display='none'; return; }
    var decoded;
    try { decoded = atob(clean); } catch(e) { showError('Decode failed: ' + e.message); return; }
    showOutput(decoded);
    var b64Bytes = new Blob([clean]).size;
    var decBytes = new Blob([decoded]).size;
    var overhead = b64Bytes > 0 ? (((b64Bytes - decBytes) / b64Bytes) * 100).toFixed(1) : '0';
    var padMatch = clean.match(/=+$/);
    var padCount = padMatch ? padMatch[0].length : 0;
    statB64.textContent  = formatBytes(b64Bytes);
    statDec.textContent  = formatBytes(decBytes);
    statOver.textContent = overhead + '%';
    statPad.textContent  = padCount + ' chars';
  }

  function encode() {
    var raw = inputEl.value;
    if (!raw) { showError('Please type some text to encode!'); return; }
    try {
      var encoded = btoa(unescape(encodeURIComponent(raw)));
      showOutput(encoded);
      var rawBytes = new Blob([raw]).size;
      var encBytes = new Blob([encoded]).size;
      statB64.textContent  = formatBytes(encBytes);
      statDec.textContent  = formatBytes(rawBytes);
      statOver.textContent = rawBytes > 0 ? (((encBytes - rawBytes) / rawBytes) * 100).toFixed(1) + '%' : '0%';
      var padMatch = encoded.match(/=+$/);
      statPad.textContent  = (padMatch ? padMatch[0].length : 0) + ' chars';
    } catch(e) { showError('Encode failed: ' + e.message); }
  }

  decodeBtn.addEventListener('click', function() {
    if (encodeMode) { decode.call = null; encode(); } else { decode(); }
  });

  encodeBtn.addEventListener('click', function() {
    encodeMode = !encodeMode;
    if (encodeMode) {
      decodeBtn.textContent = '⚡ Encode!';
      encodeBtn.textContent = 'ὐ4 Decode Instead';
      inputEl.placeholder = 'Type plain text here to encode to Base64...';
    } else {
      decodeBtn.textContent = '⚡ Decode!';
      encodeBtn.textContent = 'ὐ4 Encode Instead';
      inputEl.placeholder = 'Paste Base64 encoded data here...';
    }
    outPanel.style.display = 'none';
    hideError();
  });

  clearBtn.addEventListener('click', function() {
    inputEl.value = '';
    outputEl.value = '';
    outPanel.style.display = 'none';
    hideError();
    encodeMode = false;
    decodeBtn.textContent = '⚡ Decode!';
    encodeBtn.textContent = 'ὐ4 Encode Instead';
    inputEl.placeholder = 'Paste Base64 encoded data here... e.g. SGVsbG8gV29ybGQ=';
  });

  copyBtn.addEventListener('click', function() {
    outputEl.select();
    try { document.execCommand('copy'); } catch(e) {}
    if (navigator.clipboard) navigator.clipboard.writeText(outputEl.value).catch(function(){});
    var orig = copyBtn.textContent;
    copyBtn.textContent = '✔ COPIED!';
    copyBtn.style.background = 'var(--green)';
    setTimeout(function() {
      copyBtn.textContent = orig;
      copyBtn.style.background = 'var(--ink)';
    }, 1800);
  });

  // Example cards
  var cards = document.querySelectorAll('.example-card');
  for (var i = 0; i < cards.length; i++) {
    cards[i].addEventListener('click', function() {
      inputEl.value = this.dataset.encoded;
      encodeMode = false;
      decodeBtn.textContent = '⚡ Decode!';
      decode();
    });
  }

  // Keyboard shortcut
  inputEl.addEventListener('keydown', function(e) {
    if ((e.ctrlKey || e.metaKey) && e.key === 'Enter') { encodeMode ? encode() : decode(); }
  });

  // Preload
  inputEl.value = 'SGVsbG8gRnJvbSBEZXZEdW5pYSE=';
})();
</script>
<script src="masthead.js"></script>
<script src="hero-banner.js"></script>
<script src="author-card.js"></script>
</body>
</html>