diff --git a/jsbridge/src/main/java/com/apkfuns/jsbridge/JsBridgeImpl.java b/jsbridge/src/main/java/com/apkfuns/jsbridge/JsBridgeImpl.java
index a4792b1..62de2e8 100644
--- a/jsbridge/src/main/java/com/apkfuns/jsbridge/JsBridgeImpl.java
+++ b/jsbridge/src/main/java/com/apkfuns/jsbridge/JsBridgeImpl.java
@@ -214,6 +214,13 @@ private JsModule getModule(String moduleName) {
 
     private String getInjectJsString() {
         StringBuilder builder = new StringBuilder();
+        // Issue #35: guard the whole injection so OnJsBridgeReady
+        // fires only once per JS context. A fresh page load starts
+        // with window.<protocol> undefined and gets the bridge set
+        // up exactly once. Re-injection on the same context (for
+        // example onPageFinished firing multiple times, or sub
+        // frames triggering an extra inject call) becomes a no-op.
+        builder.append("if(!window.").append(newProtocol).append("){");
         builder.append("var ").append(className).append("=function(){");
         // 注入通用方法
         builder.append(JBUtilMethodFactory.getUtilMethods(newLoadReadyMethod));
@@ -255,6 +262,7 @@ private String getInjectJsString() {
         builder.append("};");
         builder.append("window." + newProtocol + "=new " + className + "();");
         builder.append(newProtocol + ".OnJsBridgeReady();");
+        builder.append("}");
         return builder.toString();
     }