diff --git a/docs/api.md b/docs/api.md
index abac963b..a27aee22 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -940,7 +940,7 @@ const {Browser} = require('.');
 const browser = new Browser();
 
 browser.newPage().then(async page => {
-  const watchDog = page.waitForFunction('window.innerWidth < 100);
+  const watchDog = page.waitForFunction('window.innerWidth < 100');
   page.setViewport({width: 50, height: 50});
   await watchDog;
   browser.close();