diff --git a/webapp/src/log.js b/webapp/src/log.js
new file mode 100644
index 0000000..a1ca099
--- /dev/null
+++ b/webapp/src/log.js
@@ -0,0 +1,38 @@
+export const levelDebug = 0
+export const levelInfo = 1
+export const levelWarn = 2
+export const levelError = 3
+
+let level = levelDebug
+export function setLogLevel(logLevel) {
+  level = logLevel
+}
+
+function nowStr() {
+  const now = new Date()
+  return `${now.getFullYear()}${now.getDate()}${now.getMonth()}.${now.getHours()}${now.getMinutes()}${now.getSeconds()}`
+}
+
+export function Debug(msg) {
+  if (level <= levelDebug) {
+    console.log(`[DBG ${nowStr()}] ${msg}`)
+  }
+}
+
+export function Info(msg) {
+  if (level <= levelInfo) {
+    console.log(`[INF ${nowStr()}] ${msg}`)
+  }
+}
+
+export function Warn(msg) {
+  if (level <= levelWarn) {
+    console.warn(`[WRN ${nowStr()}] ${msg}`)
+  }
+}
+
+export function Error(msg) {
+  if (level <= levelError) {
+    console.error(`[ERR ${nowStr()}] ${msg}`)
+  }
+}