add access token to readme

diff --git a/README.md b/README.md
index 2753124..6f31cb7 100644 (file)
--- a/README.md
+++ b/README.md
@@ -42,7 +42,10 @@ summation of UTXOs of one account.
 const bytom = require('bytom-sdk')
 const url = 'http://localhost:9888'
 
-const client = new bytom.Client(url)
+// access token is required when client is not in same origin with the request bytom node
+const accessToken = ''
+
+const client = new bytom.Client(url, accessToken)
 ```
 
 ## Interaction with bytom