diff --git a/qjs.c b/qjs.c
index 0254aa2..e612d89 100644
--- a/qjs.c
+++ b/qjs.c
@@ -528,11 +528,12 @@ int main(int argc, char **argv)
                  "globalThis.global = globalThis;\n"
                  "global.console.error = console.log\n"
                  "global.console.warn = console.log\n"
+                 "globalThis.break = () => { throw new Error('Break'); };\n"
                  "\n"
                  "if (typeof os !== 'undefined') {\n"
                  "    globalThis.sleep = os.sleep;\n"
-                 "    async function setTimeout(func, ms) { let cleared = false; await sleep(ms); if (!cleared) { func(); } return function clearTimeout() { cleared = true } }\n"
-                 "    globalThis.setTimeout = setTimeout\n"
+                 "    async function setTimeout2(func, ms) {globalThis.clearTimeout = false; await sleep(ms); if (!clearTimeout) { func(); } }\n"
+                 "    globalThis.setTimeout = setTimeout2\n"
                  "} else {\n"
                  "    console.error('os is not defined.');\n"
                  "}\n"