一. 使用方法：
1.Import the header file and declare an ivar property:

import "WebViewJavascriptBridge.h"

...
@property WebViewJavascriptBridge* bridge;

2. Instantiate WebViewJavascriptBridge with a WKWebView, UIWebView (iOS) or WebView (OSX):
   self.bridge = [WebViewJavascriptBridge bridgeForWebView:webView];

3. Register a handler in ObjC, and call a JS handler:
   [self.bridge registerHandler:@"ObjC Echo" handler:^(id data, WVJBResponseCallback responseCallback) {
   NSLog(@"ObjC Echo called with: %@", data);
   responseCallback(data);
   }];
   [self.bridge callHandler:@"JS Echo" data:nil responseCallback:^(id responseData) {
   NSLog(@"ObjC received response: %@", responseData);
   }];

4. Copy and paste setupWebViewJavascriptBridge into your JS:
   function setupWebViewJavascriptBridge(callback) {
   if (window.WebViewJavascriptBridge) { return callback(WebViewJavascriptBridge); }
   if (window.WVJBCallbacks) { return window.WVJBCallbacks.push(callback); }
   window.WVJBCallbacks = [callback];
   var WVJBIframe = document.createElement('iframe');
   WVJBIframe.style.display = 'none';
   WVJBIframe.src = 'https://bridge_loaded';
   document.documentElement.appendChild(WVJBIframe);
   setTimeout(function() { document.documentElement.removeChild(WVJBIframe) }, 0)
   }

5. Finally, call setupWebViewJavascriptBridge and then use the bridge to register handlers and call ObjC handlers:setupWebViewJavascriptBridge(function(bridge) {
   /* Initialize your app here */

   bridge.registerHandler('JS Echo', function(data, responseCallback) {
   console.log("JS Echo called with:", data)
   responseCallback(data)
   })
   bridge.callHandler('ObjC Echo', {'key':'value'}, function responseCallback(responseData) {
   console.log("JS received response:", responseData)
   })
   })

二. API定义
ObjC API

1. [WebViewJavascriptBridge bridgeForWebView:(WKWebVIew/UIWebView/WebView*)webview
2. [bridge registerHandler:(NSString*)handlerName handler:(WVJBHandler)handler]
3. [bridge callHandler:(NSString)handlerName data:(id)data]
   [bridge callHandler:(NSString)handlerName data:(id)data responseCallback:(WVJBResponseCallback)callback]
4. [bridge setWebViewDelegate:(id)webViewDelegate]
   Optionally, set a WKNavigationDelegate/UIWebViewDelegate if you need to respond to the [web view's lifecycle events]

三. Javascript API

1. bridge.registerHandler("handlerName", function(responseData) { ... })
2. bridge.callHandler("handlerName", data)
   bridge.callHandler("handlerName", data, function responseCallback(responseData) { ... })
3. bridge.disableJavscriptAlertBoxSafetyTimeout()
   Calling bridge.disableJavscriptAlertBoxSafetyTimeout() has the same effect as calling [bridge disableJavscriptAlertBoxSafetyTimeout]; in ObjC.