UIWebview与OC交互以及加载失败

self.webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 40, self.view.frame.size.width, self.view.frame.size.height - 20)];
NSString *path = [[NSBundle mainBundle] bundlePath];
NSURL *baseURL = [NSURL fileURLWithPath:path];
NSString * htmlPath = [[NSBundle mainBundle] pathForResource:@"index" ofType:@"html"];
NSString * htmlCont = [NSString stringWithContentsOfFile:htmlPath                                 encoding:NSUTF8StringEncoding  error:nil];
[self.webView loadHTMLString:htmlCont baseURL:baseURL];
[self.view addSubview: _webView];

  <button id="btn_submit" onclick="Login('参数1')">返回</button>

JSContext *context = [_webView  valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];

context[@"Login"] = ^() {
     //  在这里处理你要做的事情
    NSArray *args = [JSContext currentArguments];
  
    //        NSString *strUrl = args[0];
    //        NSLog(@"%@",strUrl);        
    for (id obj in args) {
        NSLog(@"%@",obj);
    } 
};

@interface ViewController ()
{
  NSURLConnection *theConnection;
}
@end
@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
UIWebView *myWebview = [[UIWebView alloc]initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
[self.view addSubview:myWebview];

NSURL *url = [NSURL URLWithString:@"https://itunesconnect.apple.com/"];
NSURLRequest *request =[NSURLRequest requestWithURL:url
                                        cachePolicy:NSURLRequestReloadIgnoringLocalCacheData
                                    timeoutInterval:10.0];
[myWebview loadRequest:request];


if (theConnection)
{
    [theConnection cancel];
// SAFE_RELEASE(theConnection);
    NSLog(@"safe release connection");
   }
theConnection= [[NSURLConnection alloc]initWithRequest:request delegate:self startImmediately:YES];
}

-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
if (theConnection) {
//  SAFE_RELEASE(theConnection);
    NSLog(@"safe release connection");
}

if ([response isKindOfClass:[NSHTTPURLResponse class]]){
    
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse*)response;
    if ((([httpResponse statusCode]/100) == 2)){
        NSLog(@"connection ok");
    }
    else{
        NSError *error = [NSError errorWithDomain:@"HTTP" code:[httpResponse statusCode] userInfo:nil];
        if ([error code] == 404){
            NSLog(@"404");
            [self webViewFail];
        }
       else if ([error code] == 403){
            NSLog(@"403");
            [self webViewFail];
        }
    }
  }
 }

-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
  {
if (theConnection) {
//  SAFE_RELEASE(theConnection);
    NSLog(@"safe release connection");
     [self webViewFail];
}
if (error.code == 22) //The operation couldn’t be completed. Invalid argument
{
    NSLog(@"22");
 [self webViewFail];
}
else if (error.code == -1001) //The request timed out.  webview code -999的时候会收到－1001
{
    NSLog(@"-1001");
 [self webViewFail];
}
else if (error.code == -1005) //The network connection was lost.
{
    NSLog(@"-1005");
 [self webViewFail];
}
else if (error.code == -1009) //The Internet connection appears to be offline
{
    NSLog(@"-1009");
     [self webViewFail];
}
}

- (void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error
{
/*
didFailLoadWithError中出现code ＝ -999错误。
 错误原因：一个页面没有被加载完成之前，收到下一个请求。
  */ 
 CLog(@"error%@",error);

if ([error code] == NSURLErrorCancelled) {
    return;
}

 [self webViewFail];
}


- (void)webViewFail
 {
UILabel *content = [[UILabel alloc]initWithFrame:(CGRectMake(20, 100, 300, 100))];

NSString *originStr = @"Hello,中秋节！";
NSMutableAttributedString *attributedStr01 = [[NSMutableAttributedString alloc] initWithString: originStr];
[attributedStr01 addAttribute: NSForegroundColorAttributeName value: [UIColor blueColor] range: NSMakeRange(0, 4)];
//分段控制，第5个字符开始的3个字符，即第5、6、7字符设置为红色
[attributedStr01 addAttribute: NSForegroundColorAttributeName value: [UIColor redColor] range: NSMakeRange(4, 3)];

//赋值给显示控件label01的 attributedText
content.attributedText = attributedStr01;
[self.view addSubview:content];


// 这里为加载静态页面，进行展示错误信息
//   UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)]; 
 //   NSString *path = [[NSBundle mainBundle] bundlePath];
//   NSURL *baseURL = [NSURL fileURLWithPath:path];
//    NSString * htmlPath = [[NSBundle mainBundle] pathForResource:@"webError" ofType:@"html"];
//    NSString * htmlCont = [NSString stringWithContentsOfFile:htmlPath encoding:NSUTF8StringEncoding error:nil];
//    [webView loadHTMLString:htmlCont baseURL:baseURL];
//  [self.view addSubview: webView];
//     JS 调用 OC
//     1、首先导入库 JavaScriptCore.framework
//   JSContext *context = [webView  valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
//   context[@"btnSubmit"] = ^() {            
//    NSLog(@"返回上一页");
//  };
 }