Added transmit frontend call

www/main.js

@@ -1 +1,37 @@
+async function POST(path, data={}) {
+    return new Promise(function (onSuccess, onError) {
+        var xhr = new XMLHttpRequest();
+        xhr.open('POST', path, true);
+        xhr.setRequestHeader('Content-Type', 'application/json');
+        xhr.onreadystatechange = function () {
+            if (xhr.readyState === 4) {
+                if (xhr.status === 200) {
+                    onSuccess(xhr);
+                } else {
+                    onError(xhr);
+                }
+            }
+        };
+
+        xhr.onerror = () => onError(xhr);
+        xhr.send(JSON.stringify(data));
+    });
+}
+
+function assert(condition, message) {
+    if (!condition) {
+        throw message || "Assertion failed";
+    }
+}
+
+
+async function transmit(transmitterID, channel, action, intensity=0, lucalEncoded=false) {
+    assert(typeof transmitterID === 'number');
+    assert(typeof channel === 'number');
+    assert(['shock', 'vibrate', 'beep'].includes(action));
+    assert(typeof intensity === 'number');
+    assert(typeof lucalEncoded === 'boolean');
+    POST('/transmit', {transmitterID: transmitterID, channel: channel, action: action, intensity: intensity, lucalEncoded: lucalEncoded});
+}
+
 console.debug('Main loaded!');