- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {

  NSLog(@"开始请求webview:%@",request.URL.relativeString);
  return YES;

}
 - (void)webViewDidStartLoad:(UIWebView *)webView {
    NSLog(@"开始加载webview");  
}
- (void)webViewDidFinishLoad:(UIWebView *)webView { 
   NSLog(@"结束加载webview");  
}  
- (void)webView:(UIWebView *)webView didFailLoadWithError:(nonnull NSError *)error {
 　　 NSLog(@"webView加载失败");
 }

- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler {
  NSLog(@"webview开始请求");
  decisionHandler(WKNavigationActionPolicyAllow);
}
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation {
  NSLog(@"webView开始加载");
}
- (void)webView:(WKWebView *)webView decidePolicyForNavigationResponse:(WKNavigationResponse *)navigationResponse decisionHandler:(void (^)(WKNavigationResponsePolicy))decisionHandler {
  NSLog(@"webview开始收到响应");
  decisionHandler(WKNavigationResponsePolicyAllow);
}

-----------------显示开始加载html CSS js 和图片资源等（JS引擎单线程顺序执行）---------------

- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation {
  NSLog(@"1");
}
- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation {
  NSLog(@"webview结束加载内容");
}
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation withError:(NSError *)error{
  NSLog(@"webview加载失败");
}
- (void)webView:(WKWebView *)webView didReceiveServerRedirectForProvisionalNavigation:(WKNavigation *)navigation{
  NSLog(@"开始重定向的函数");
}
- (void)webView:(WKWebView *)webView didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge *)challenge completionHandler:(void (^)(NSURLSessionAuthChallengeDisposition, NSURLCredential *))completionHandler
{
  NSLog(@"2");
  completionHandler(NSURLSessionAuthChallengePerformDefaultHandling, nil);
}

document.write( " <script src='test.js?rnd= " + Math.random() + " '></s " + " cript> " )

var js = document.createElement( " script " )

js.src = " test.js " + Math.random()

document.body.appendChild(js)

<script src="test.js?ver=113"></script>

- (void)removeWebCache{
  if ([[UIDevice currentDevice].systemVersion floatValue] >= 9.0) {
    NSSet *websiteDataTypes= [NSSet setWithArray:@[
                            WKWebsiteDataTypeDiskCache,
                            //WKWebsiteDataTypeOfflineWebApplication
                            WKWebsiteDataTypeMemoryCache,
                            //WKWebsiteDataTypeLocal
                            WKWebsiteDataTypeCookies,
                            //WKWebsiteDataTypeSessionStorage,
                            //WKWebsiteDataTypeIndexedDBDatabases,
                            //WKWebsiteDataTypeWebSQLDatabases
                            ]];
    
    // All kinds of data
    //NSSet *websiteDataTypes = [WKWebsiteDataStore allWebsiteDataTypes];
    NSDate *dateFrom = [NSDate dateWithTimeIntervalSince1970:0];
    [[WKWebsiteDataStore defaultDataStore] removeDataOfTypes:websiteDataTypes modifiedSince:dateFrom completionHandler:^{
      
    }];
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
    
  } else {
    //先删除cookie
    NSHTTPCookie *cookie;
    NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
    for (cookie in [storage cookies])
    {
      [storage deleteCookie:cookie];
    }
    
    NSString *libraryDir = [NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSString *bundleId = [[[NSBundle mainBundle] infoDictionary]
                objectForKey:@"CFBundleIdentifier"];
    NSString *webkitFolderInLib = [NSString stringWithFormat:@"%@/WebKit",libraryDir];
    NSString *webKitFolderInCaches = [NSString
                     stringWithFormat:@"%@/Caches/%@/WebKit",libraryDir,bundleId];
    NSString *webKitFolderInCachesfs = [NSString
                      stringWithFormat:@"%@/Caches/%@/fsCachedData",libraryDir,bundleId];
    NSError *error;
    /* iOS8.0 WebView Cache的存放路径 */
    [[NSFileManager defaultManager] removeItemAtPath:webKitFolderInCaches error:&error];
    [[NSFileManager defaultManager] removeItemAtPath:webkitFolderInLib error:nil];
    /* iOS7.0 WebView Cache的存放路径 */
    [[NSFileManager defaultManager] removeItemAtPath:webKitFolderInCachesfs error:&error];
    NSString *cookiesFolderPath = [libraryDir stringByAppendingString:@"/Cookies"];
    [[NSFileManager defaultManager] removeItemAtPath:cookiesFolderPath error:&error];
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
  }
}

  - (void)webViewDidFinishLoad:(UIWebView *)webView
  {
    //防止内存泄漏
    [[NSUserDefaults standardUserDefaults] setInteger:0 forKey:@"WebKitCacheModelPreferenceKey"];
    //本地webkit硬盘图片的缓存；
    [[NSUserDefaults standardUserDefaults] setBool:NO forKey:@"WebKitDiskImageCacheEnabled"];//自己添加的，原文没有提到。
    //静止webkit离线缓存
    [[NSUserDefaults standardUserDefaults] setBool:NO forKey:@"WebKitOfflineWebApplicationCacheEnabled"];//自己添加的，，原文没有提到。
    [[NSUserDefaults standardUserDefaults] synchronize];
  }

  - (void)dealloc
  {
    [webView loadHTMLString:@"" baseURL:nil];
    [webView stopLoading];
    [webView removeFromSuperview];
    webView = nil;
    [[NSURLCache sharedURLCache] removeAllCachedResponses]; 
    [[NSURLCache sharedURLCache] setDiskCapacity:0]; 
    [[NSURLCache sharedURLCache] setMemoryCapacity:0]; 
    NSLog(@"释放了webview");
  }


  - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{ 
     int cacheSizeMemory = 4*1024*1024; // 4MB int      

     cacheSizeDisk = 32*1024*1024; // 32MB 
     NSURLCache *sharedCache = [[NSURLCache alloc] initWithMemoryCapacity:cacheSizeMemory diskCapacity:cacheSizeDisk diskPath:@"nsurlcache"];
     [NSURLCache setSharedURLCache:sharedCache]; 
  ｝ 
  - (void)applicationDidReceiveMemoryWarning:(UIApplication *)application { 
     [[NSURLCache sharedURLCache] removeAllCachedResponses];
  }

<script type="text/javascript" src="index1.js?v=1.0.0"></script>