diff --git a/main.c b/main.c
index bbc5f2f..877bebb 100644
--- a/main.c
+++ b/main.c
@@ -356,6 +356,8 @@ main(int argc, char **argv)
 	}
 
 	if (interactive) {
+		printf("Welcome to MuJS %d.%d.%d.\n",
+			JS_VERSION_MAJOR, JS_VERSION_MINOR, JS_VERSION_PATCH);
 		if (isatty(0)) {
 			using_history();
 			rl_bind_key('\t', rl_insert);
diff --git a/mujs.h b/mujs.h
index 421e81a..a62c7fe 100644
--- a/mujs.h
+++ b/mujs.h
@@ -7,6 +7,13 @@
 extern "C" {
 #endif
 
+#define JS_VERSION_MAJOR 1
+#define JS_VERSION_MINOR 2
+#define JS_VERSION_PATCH 0
+
+#define JS_VERSION (JS_VERSION_MAJOR * 10000 + JS_VERSION_MINOR * 100 + JS_VERSION_PATCH)
+#define JS_CHECKVERSION(x,y,z) (JS_VERSION >= ((x) * 10000 + (y) * 100 + (z)))
+
 /* noreturn is a GCC extension */
 #ifdef __GNUC__
 #define JS_NORETURN __attribute__((noreturn))