diff --git a/rln-js/index.html b/rln-js/index.html
index 59a3016..1afcb27 100644
--- a/rln-js/index.html
+++ b/rln-js/index.html
@@ -9,21 +9,23 @@
 
 <body>
 
-<div><h1>RLN</h1>
-    <div><h2>Wallet</h2>
-        <div id='wallet'></div>
-        <button disabled id='connect-wallet' type='button'>Connect Wallet</button>
+<div><h1>Waku RLN</h1>
+    <div><h2>Blockchain</h2>
+        <div><h3>Wallet</h3>
+            <p>Address: <span id='address'></span></p>
+            <button disabled id='connect-wallet' type='button'>Connect Wallet</button>
+        </div>
+        <div><h3>Contract Data</h3>
+            <p>Latest membership id on contract: <span id='latest-membership-id'></span></p>
+            <button disabled id='retrieve-rln-details' type='button'>Retrieve contract state from blockchain
+            </button>
+        </div>
     </div>
 
-    <div><h2>RLN</h2>
-        <button disabled id='retrieve-rln-details' type='button'>Retrieve RLN contract state from blockchain</button>
-    </div>
-
-    <p>You can either generate new credentials:</p><br/>
-    <button disabled id='generate-credentials' type='button'>Generate RLN Credentials</button>
-    <p>Or import existing ones:</p><br/>
-
-    <div>
+    <div><h2>Credentials</h2>
+        <p>You can either generate new credentials:</p>
+        <button disabled id='generate-credentials' type='button'>Generate RLN Credentials</button>
+        <p>Or import existing ones:</p>
         <label for="membership-id">Membership ID (your index in the RLN smart contract):</label>
         <input id="membership-id" name="membership-id" type="text"><br>
         <label for="id-key">RLN Identity Key (hex string):</label>
@@ -31,49 +33,44 @@
         <label for="commitment-key">RLN Commitment Key (hex string):</label>
         <input id="commitment-key" name="commitment-key" type="text"><br>
         <button disabled id='import-button' type='button'>Import RLN Credentials</button>
-    </div>
 
-    <div><h2>Credentials</h2>
-        <div><h3>Membership id</h3>
-            <div id="id"></div>
-        </div>
-        <div><h3>Key</h3>
-            <div id="key"></div>
-        </div>
-        <div><h3>Commitment</h3>
-            <div id="commitment"></div>
-        </div>
+        <p><strong>Membership id: </strong><span id="id">none</span></p>
+        <p><strong>Key: </strong><span id="key">none</span></p>
+        <p><strong>Commitment: </strong><span id="commitment">none</span></p>
+
         <button disabled id='register-button' type='button'>Register Credentials in Contract</button>
     </div>
-</div>
 
-<div><h1>Waku</h1>
-    <div id='status'></div>
-    <br/>
+    <div><h1>Waku</h1>
+        <div id='status'></div>
 
-    <label for='remote-multiaddr'>Remote peer's multiaddr</label>
-    <input id='remote-multiaddr'
-           type='text'
-           value="/dns4/node-01.ac-cn-hongkong-c.wakuv2.test.statusim.net/tcp/443/wss/p2p/16Uiu2HAkvWiyFsgRhuJEb9JfjYxEkoHLgnUQmr1N5mKWnYjxYRVm">
-    <button disabled id='dial' type='button'>Dial</button>
-    <br/>
-    <label for='nick-input'>Your nickname</label>
-    <input id='nick-input' placeholder='Choose a nickname' type='text'>
-    <button disabled id='set-nick' type='button'>Set nickname</button>
-    <br/>
+        <label for='remote-multiaddr'>Remote peer's multiaddr</label>
+        <input id='remote-multiaddr'
+               type='text'
+               value="/dns4/node-01.ac-cn-hongkong-c.wakuv2.test.statusim.net/tcp/443/wss/p2p/16Uiu2HAkvWiyFsgRhuJEb9JfjYxEkoHLgnUQmr1N5mKWnYjxYRVm">
+        <button disabled id='dial' type='button'>Dial</button>
+        <br/>
+        <label for='nick-input'>Your nickname</label>
+        <input id='nick-input' placeholder='Choose a nickname' type='text'>
+        <button disabled id='set-nick' type='button'>Set nickname</button>
+        <br/>
 
-    <label for='textInput'>Message text</label>
-    <input disabled id='textInput' placeholder='Type your message here' type='text'>
-    <button disabled id='sendButton' type='button'>Send message using Light Push</button>
-    <br/>
-    <div id="messages"></div>
+        <label for='textInput'>Message text</label>
+        <input disabled id='textInput' placeholder='Type your message here' type='text'>
+        <button disabled id='sendButton' type='button'>Send message using Light Push</button>
+        <br/>
+        <div id="messages"></div>
+    </div>
 </div>
 
 <script type='module'>
     import {utils} from 'https://unpkg.com/js-waku@0.29.0-29436ea/bundle/index.js';
     import {createLightNode} from 'https://unpkg.com/js-waku@0.29.0-29436ea/bundle/lib/create_waku.js'
     import {waitForRemotePeer} from 'https://unpkg.com/js-waku@0.29.0-29436ea/bundle/lib/wait_for_remote_peer.js'
-    import {EncoderV0, DecoderV0} from 'https://unpkg.com/js-waku@0.29.0-29436ea/bundle/lib/waku_message/version_0.js'
+    import {
+        EncoderV0,
+        DecoderV0
+    } from 'https://unpkg.com/js-waku@0.29.0-29436ea/bundle/lib/waku_message/version_0.js'
 
     import {protobuf} from "https://taisukef.github.io/protobuf-es.js/dist/protobuf-es.js";
 
@@ -86,43 +83,44 @@
 
     import {ethers} from "https://unpkg.com/ethers@5.0.7/dist/ethers-all.esm.min.js"
 
-    // RLN Elements
+    // Blockchain Elements
+    const addressDiv = document.getElementById('address');
+    const connectWalletButton = document.getElementById('connect-wallet');
+
+    const latestMembershipSpan = document.getElementById('latest-membership-id')
+    const retrieveRLNDetailsButton = document.getElementById('retrieve-rln-details')
+
+    // Credentials Elements
     const generateCredsButton = document.getElementById('generate-credentials')
-    const idDiv = document.getElementById('id');
-    const keyDiv = document.getElementById('key');
-    const commitmentDiv = document.getElementById('commitment');
+
     const membershipIdInput = document.getElementById('membership-id')
     const identityKeyInput = document.getElementById('id-key')
     const commitmentKeyInput = document.getElementById('commitment-key')
     const importButton = document.getElementById('import-button')
-    const connectWalletButton = document.getElementById('connect-wallet');
-    const retrieveRLNDetailsButton = document.getElementById('retrieve-rln-details')
+
+    const idDiv = document.getElementById('id');
+    const keyDiv = document.getElementById('key');
+    const commitmentDiv = document.getElementById('commitment');
+
     const registerButton = document.getElementById('register-button');
 
     // Waku Elements
     const statusDiv = document.getElementById('status');
 
-    const dialButton = document.getElementById('dial')
     const remoteMultiAddrInput = document.getElementById('remote-multiaddr')
+    const dialButton = document.getElementById('dial')
 
     const nicknameInput = document.getElementById('nick-input')
     const setNickButton = document.getElementById('set-nick')
 
     const textInput = document.getElementById('textInput');
     const sendButton = document.getElementById('sendButton');
-    const walletDiv = document.getElementById('wallet');
 
     const messagesDiv = document.getElementById('messages')
 
-    let membershipId;
-    let membershipKey;
-    let encoder;
-    let node;
-    let nodeConnected;
-    let nick;
+    let membershipId, membershipKey, encoder, node, nodeConnected, nick, rlnInstance;
     let retrievedRLNEvents = false;
-    let rlnInstancePromise = create();
-    let rlnInstance;
+    const rlnInstancePromise = create();
 
     // Load zero-kit WASM blob.
     rlnInstancePromise.then((_rlnInstance) => {
@@ -131,13 +129,22 @@
         connectWalletButton.disabled = false;
     })
 
+    const ContentTopic = "/toy-chat/2/luzhou/proto";
+
+    // Protobuf
+    const ProtoChatMessage = new protobuf.Type("ChatMessage")
+        .add(new protobuf.Field("timestamp", 1, "uint64"))
+        .add(new protobuf.Field("nick", 2, "string"))
+        .add(new protobuf.Field("text", 3, "bytes"));
+
+    // Function to update the fields to guide the user by disabling buttons.
     const updateFields = () => {
         if (membershipKey) {
             keyDiv.innerHTML = utils.bytesToHex(membershipKey.IDKey)
             commitmentDiv.innerHTML = utils.bytesToHex(membershipKey.IDCommitment)
             idDiv.innerHTML = membershipId || "-"
 
-            if (membershipId) {
+            if (membershipId && rlnInstance) {
                 encoder = new RLNEncoder(
                     new EncoderV0(ContentTopic),
                     rlnInstance,
@@ -147,6 +154,8 @@
             }
         }
 
+        registerButton.disabled = !(membershipKey && retrievedRLNEvents && !membershipId)
+
         importButton.disabled = !(membershipIdInput.value
             && identityKeyInput.value
             && commitmentKeyInput.value);
@@ -158,8 +167,12 @@
         setNickButton.disabled = !nicknameInput.value;
 
         dialButton.disabled = !(node && node.isStarted() && retrievedRLNEvents)
+
+        retrieveRLNDetailsButton.disabled = !retrievedRLNEvents;
     }
 
+    // Blockchain
+
     generateCredsButton.onclick = () => {
         membershipKey = rlnInstance.generateMembershipKey()
         updateFields();
@@ -177,13 +190,6 @@
         updateFields()
     }
 
-    // Protobuf
-    const ProtoChatMessage = new protobuf.Type("ChatMessage")
-        .add(new protobuf.Field("timestamp", 1, "uint64"))
-        .add(new protobuf.Field("nick", 2, "string"))
-        .add(new protobuf.Field("text", 3, "bytes"));
-
-    // Wallet
     const checkChain = async (chainId) => {
         retrieveRLNDetailsButton.disabled = retrievedRLNEvents || chainId !== 5;
         registerButton.disabled = !(chainId === 5 && retrievedRLNEvents);
@@ -192,11 +198,6 @@
         }
     }
 
-    const checkCurrentChain = async () => {
-        const network = await provider.getNetwork();
-        checkChain(network.chainId);
-    }
-
     const rlnDeployBlk = 7677135;
     const rlnAddress = "0x367F3e869cF2E1DD28644E308b42652cb6fcDA72";
     const rlnAbi = [
@@ -216,22 +217,28 @@
         try {
             const idCommitment = ethers.utils.zeroPad(ethers.utils.arrayify(pubkey), 32);
             rlnInstance.insertMember(idCommitment);
-            console.debug("IDCommitment registered in tree", idCommitment, index.toNumber());
+            const indexInt = index.toNumber()
+            console.log("index", index)
+            if (!latestMembershipSpan.innerText || indexInt > latestMembershipSpan.innerText) {
+                latestMembershipSpan.innerText = indexInt
+            }
+            console.debug("IDCommitment registered in tree", idCommitment, indexInt);
         } catch (err) {
-            alert(err); // TODO: the merkle tree can be in a wrong state. The app should be disabled
+            console.error(err); // TODO: the merkle tree can be in a wrong state. The app should be disabled
         }
     }
 
     const setAccounts = acc => {
         accounts = acc;
-        walletDiv.innerHTML = accounts.length ? accounts[0] : "";
+        addressDiv.innerHTML = accounts.length ? accounts[0] : "";
     }
 
     connectWalletButton.onclick = async () => {
         try {
             accounts = await provider.send("eth_requestAccounts", []);
             setAccounts(accounts);
-            checkCurrentChain();
+            const network = await provider.getNetwork();
+            checkChain(network.chainId);
         } catch (e) {
             console.log("No web3 provider available", e);
         }
@@ -248,13 +255,7 @@
             handleMembership(event.args.pubkey, event.args.index, event);
         });
 
-        alert("Loaded all events from contract");
         retrievedRLNEvents = true;
-        // TODO: at this point it should be possible to register a credential and send messages
-        // TODO: emit an event to enable message form and register button
-
-        retrieveRLNDetailsButton.disabled = true;
-        registerButton.disabled = false;
 
         // reacting to new registrations
         rlnContract.on(filter, (pubkey, index, event) => {
@@ -357,7 +358,7 @@
         updateMessages()
     }
 
-    const ContentTopic = "/toy-chat/2/luzhou/proto";
+
     (async () => {
         statusDiv.innerHTML = '<p>Creating Waku node.</p>';
         node = await createLightNode();
