注意以下枚舉

/*! @enum WKUserScriptInjectionTime
 @abstract when a user script should be injected into a webpage.
 @constant WKUserScriptInjectionTimeAtDocumentStart    Inject the script after the document element has been created, but before any other content has been loaded.
 @constant WKUserScriptInjectionTimeAtDocumentEnd      Inject the script after the document has finished loading, but before any subresources may have finished loading.
 */
NS_ASSUME_NONNULL_BEGIN

typedef NS_ENUM(NSInteger, WKUserScriptInjectionTime) {
    WKUserScriptInjectionTimeAtDocumentStart,
    WKUserScriptInjectionTimeAtDocumentEnd
} API_AVAILABLE(macos(10.10), ios(8.0));

修改js系統(tǒng)方法實(shí)現(xiàn)（alert為例）

• 例1：
  • js代碼

          <input type="button" value="重定義系統(tǒng)方法" onclick="locationClick()" />
          function locationClick() {
               alert('4444')
           }
  

  • OC代碼注入

   // 以下兩種注入方式都可以
   NSString *jsCode = @"alert = (function (oriAlertFunc){ \
                         return function(task)\
                         {\
                          window.webkit.messageHandlers.ocZRAction.postMessage(task);\
                           oriAlertFunc.call(alert,task);\
                         }\
                         })(alert);";
   NSString *jsCode3 = @"alert =  function(task)\
      {\
       window.webkit.messageHandlers.asyncAction.postMessage(task);\
      }";
   [self.webView.configuration.userContentController addUserScript:[[WKUserScript alloc] initWithSource:jsCode injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:YES]];
  
  

注入JS未實(shí)現(xiàn)方法（alert為例）

• 例1馒吴、
  • JS代碼

          <input type="button" value="注入JS未實(shí)現(xiàn)方法" onclick="shareClick()" />
  

  • OC代碼注入 注意：這里使用WKUserScriptInjectionTimeAtDocumentEnd或injectionTime:WKUserScriptInjectionTimeAtDocumentStart都可以

      NSString *jsCode6 = @"shareClick =  function(task)\
             {\
              window.webkit.messageHandlers.GoBack.postMessage(task);\
             }";
    [self.webView.configuration.userContentController addUserScript:[[WKUserScript alloc] initWithSource:jsCode6 injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES]];
    [self.webView.configuration.userContentController addUserScript:[[WKUserScript alloc] initWithSource:jsCode6 injectionTime:WKUserScriptInjectionTimeAtDocumentStart forMainFrameOnly:YES]];
  

修改JS方法的原有實(shí)現(xiàn)

• 例1稠茂、
  • JS代碼

       <input type="button" value="重定義JS方法實(shí)現(xiàn)" onclick="colorClick()" />
      function colorClick() {
                alert('55555')
           }
  

  • OC代碼
    注意：這里使用WKUserScriptInjectionTimeAtDocumentEnd不能用WKUserScriptInjectionTimeAtDocumentStart

    NSString *jsCode7 = @"colorClick =  function(task)\
                {\
                 window.webkit.messageHandlers.GoBack.postMessage(task);\
                }";
     [self.webView.configuration.userContentController addUserScript:[[WKUserScript alloc] initWithSource:jsCode7 injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES]];