atic int call_callback(js_State *J, const char *arg1, int arg2)
{
	int result;

	/* Find the function to call. */
	js_getglobal(J, "my_callback");

	/* Push arguments to function. */
	js_pushnull(J); /* the 'this' object to use */
	js_pushstring(J, arg1);
	js_pushnumber(J, arg2);

	/* Call function and check for exceptions. */
	if (js_pcall(J, 2)) {
		fprintf(stderr, "an exception occurred in the javascript callback\n");
		js_pop(J, 1);
		return -1;
	}

	/* Retrieve return value. */
	result = js_tonumber(J,