update how to get user account

Author: yupnano

README.md

@@ -24,7 +24,30 @@ We will keep improving this extension, and any suggestions are welcome!
 
 Now WebExtensionApp supports two different ways to communicate with Dapp page.
 
-#### 3.1 Using `postMessage`
+
+#### 3.1 Using NebPay SDK
+
+Please refer to Dapp Example [SuperDictionary](https://github.com/15010159959/super-dictionary) to learn how to use this extension.
+ 
+When developing your Dapp page, you can use [NebPay SDK](https://github.com/nebulasio/nebPay) to communicate with ExtensionWallet. Just as the example below.
+
+To call a SmartContract through extensionWallet, you should use [`nebpay.call`](https://github.com/nebulasio/nebPay/blob/master/doc/NebPay_Introduction.md#call) or [`nebpay.simulateCall`](https://github.com/nebulasio/nebPay/blob/master/doc/NebPay_Introduction.md#simulatecall) to send a transaction as below:
+```js
+nebPay.call(to, value, callFunction, callArgs, {
+    qrcode: {
+        showQRCode: true
+    },
+    listener: cbCallDapp //specify a listener to handle the transaction result
+});
+
+function cbCallDapp(resp){
+        console.log("response: " + JSON.stringify(resp))
+    }
+    
+```
+
+
+#### 3.2 Using `postMessage`
 
 When developing your Dapp page, you can use `postMessage` API to communicate with ExtensionWallet, and use `window.addEventListener` to listen the message answer. Just as the example below.
 
@@ -54,27 +77,47 @@ window.addEventListener('message', function(e) {
 })
 ```
 
-#### 3.2 Using NebPay SDK
+### 4 how to get account address
 
-Please refer to Dapp Example [SuperDictionary](https://github.com/15010159959/super-dictionary) to learn how to use this extension.
- 
-When developing your Dapp page, you can also use [NebPay SDK](https://github.com/nebulasio/nebPay) to communicate with ExtensionWallet. Just as the example below.
+It is useful for Dapp to get the current account address in the extension. Here is the explanation on how to achive this.
 
-To call a SmartContract through extensionWallet, you should use [`nebpay.call`](https://github.com/nebulasio/nebPay/blob/master/doc/NebPay_Introduction.md#call) or [`nebpay.simulateCall`](https://github.com/nebulasio/nebPay/blob/master/doc/NebPay_Introduction.md#simulatecall) to send a transaction as below:
+Method 1:
 ```js
-nebPay.call(to, value, callFunction, callArgs, {
-    qrcode: {
-        showQRCode: true
-    },
-    listener: cbCallDapp //specify a listener to handle the transaction result
-});
-
-function cbCallDapp(resp){
-        console.log("response: " + JSON.stringify(resp))
+var userAddrerss;
+
+function getUserAddress() {
+    console.log("********* get account ************")
+    window.postMessage({
+        "target": "contentscript",
+        "data":{
+        },
+        "method": "getAccount",
+    }, "*");
+}
+// listen message from contentscript
+window.addEventListener('message', function(e) {
+    // e.detail contains the transferred data (can
+    console.log("recived by page:" + e + ", e.data:" + JSON.stringify(e.data));
+    if (!!e.data.data.account) {
+        userAddrerss = e.data.data.account;
     }
-    
+})
+
+```
+
+Method 2:
+A module `NasExtWallet` is injected to your page if NasExtWallet is installed, then you can use the code below to get user account: 
+```js
+var userAddrerss;
+function callback(addr){
+    userAddrerss = addr;
+}
+
+NasExtWallet.getUserAddress(callback)
+
 ```
 
+
 ### example page
 And you can use `example/TestPage.html` to take a test.
 

inpage.js

@@ -4,6 +4,33 @@ var webExtensionWallet = "for nebulas";
 
 console.log("webExtensionWallet is defined:" + webExtensionWallet);
 
+var _NasExtWallet = function () {
+    this.getUserAddressCallback ;
+
+    this.getUserAddress = function(callback) {
+        //console.log("********* get account ************")
+        getUserAddressCallback = callback
+        window.postMessage({
+            "target": "contentscript",
+            "data":{
+            },
+            "method": "getAccount",
+        }, "*");
+    }
+
+// listen message from contentscript
+    window.addEventListener('message', function(e) {
+        // e.detail contains the transferred data (can
+        if (!!e.data.data.account) {
+            userAddrerss = e.data.data.account;
+            if(typeof getUserAddressCallback === 'function'){
+                getUserAddressCallback(userAddrerss)
+            }
+        }
+    })
+}
+
+var NasExtWallet = new _NasExtWallet()