add popup.js and background

popup.js

@@ -0,0 +1,14 @@
+document.getElementById('connectBtn').addEventListener('click', () => {
+    let wsUrl = document.getElementById('wsUrl').value;
+    if (!wsUrl) {
+        wsUrl = 'ws://127.0.0.1:8881/?token=a'
+    }
+    const msg = {
+        action: "connectWebsocket", url: wsUrl,
+    };
+    chrome.runtime.sendMessage(msg)
+})
+
+chrome.runtime.onMessage.addListener((msg, sender, sendResponse) => {
+    document.getElementById("wsStatus").innerText = msg.status;
+});