在自動填充後在UIWebView中執行Javascript後驗證標籤的長度

Question

爲了清楚起見，我將分解我的問題。

目標：

執行一些JavaScript檢查一個元素的頁面ONCE後;但如果不正確，我希望能夠按下按鈕重新檢查它。

我已經試過：

 -(IBAction)signin { 

    [passwordTF resignFirstResponder]; 
    [usernameTF resignFirstResponder]; 

    //create js strings 
    NSString *loadUsernameJS = [NSString stringWithFormat:@"var field = document.getElementById('login-form-username'); field.value='%@';", username]; 

    NSString *loadPasswordJS = [NSString stringWithFormat:@"var field = document.getElementById('login-form-password'); field.value='%@';", password]; 

    //autofill the form 
    [mainWebView stringByEvaluatingJavaScriptFromString:loadUsernameJS]; 
    [mainWebView stringByEvaluatingJavaScriptFromString:loadPasswordJS]; 

    //auto login 
    [mainWebView stringByEvaluatingJavaScriptFromString:@"document.getElementById('submit-login').click();"]; 


} 

- (void)webViewDidFinishLoad:(UIWebView *)webView { 

    NSLog(@"webViewDidiFinishLoad called"); 

    if (shouldVerify == YES) { 

     NSLog(@"webViewDidiFinishLoad - shouldVerify YES"); 

     NSString *failedLogin = [mainWebView stringByEvaluatingJavaScriptFromString: @"document.getElementById('login-msg')"]; 

     if ([failedLogin isEqualToString:@"Failed login"]) { 

      NSLog(@"webViewDidiFinishLoad - shouldVerify YES - failed"); 

      UIAlertView *WCE = [[UIAlertView alloc] initWithTitle:@"Wrong Credentials" message:@"The username or password you entered is incorrect please try again." delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; 
      [WCE show]; 

      [keychainItem resetKeychainItem]; 

      password = [keychainItem objectForKey:(__bridge id)(kSecValueData)]; 
      username = [keychainItem objectForKey:(__bridge id)(kSecAttrAccount)]; 

      [usernameTF setText:username]; 
      [passwordTF setText:password]; 


     } else { 

      NSLog(@"webViewDidiFinishLoad - shouldVerify YES - success"); 

      ViewController *viewController = [[UIStoryboard storyboardWithName:@"Main" bundle:nil] instantiateViewControllerWithIdentifier:@"ViewController"]; 

      UINavigationController *navBar=[[UINavigationController alloc]initWithRootViewController:viewController]; 

      navBar.navigationBarHidden = YES; 

      [self presentViewController:navBar animated:YES completion:nil]; 
     } 

     shouldVerify = NO; 
    } 
} 

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

    if (navigationType == UIWebViewNavigationTypeOther) { 

     NSLog(@"shouldStartLoadWithRequest - shouldVerify YES"); 

     shouldVerify = YES; 

    } else { 

     NSLog(@"shouldStartLoadWithRequest - shouldVerify NO"); 

     shouldVerify = NO; 

    } 

    return YES; 
} 

問題：

出於某種原因在這裏：

if ([failedLogin isEqualToString:@"Failed login"]) { 

      NSLog(@"webViewDidiFinishLoad - shouldVerify YES - failed"); 

      UIAlertView *WCE = [[UIAlertView alloc] initWithTitle:@"Wrong Credentials" message:@"The username or password you entered is incorrect please try again." delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil, nil]; 
      [WCE show]; 


     } else { 

      NSLog(@"webViewDidiFinishLoad - shouldVerify YES - success"); 

     } 

if語句總是返回false和

NSLog(@"webViewDidiFinishLoad - shouldVerify YES - success"); 

當它不應該和失敗登錄等於@「失敗登錄」時被打印出來。如果我刪除了else語句，它總是會驗證if語句是否爲false登錄憑據，這就是爲什麼我認爲在應該處理它之前檢查它的原因。

我的猜測：

我if語句時webView的尚未執行完畢的JavaScript和/或重裝按鈕，點擊後網頁運行此。

資源：

我不知道如何可以幫助，但我與工作的網站：tapgram.com/login

完整當前的代碼可以在這裏找到：http://pastebin.com/dnCn62FP 對於完整的projet代碼請評論，我會添加鏈接。

Answer 1

錯誤出現在JavaScript中。

NSString *failedLogin = [mainWebView 
stringByEvaluatingJavaScriptFromString:@"document.getElementById('login-msg')"]; 

返回登錄-MSG元素的完整的HTML字符串。

所以基本上你在比較Failed login和<h4 id=​"login-msg" style=​"color:​red;​">​Failed login​</h4>。

JavaScript的應該是這樣的 document.getElementById('login-msg').innerText將返回登錄失敗的情況下，登錄真正失敗。