iOS开发-WKWebView获取webview的title

1. 常用的方法，WKWebView的代理方法：

//执行JS方法获取导航栏标题
    [webView evaluateJavaScript:@"document.title" completionHandler:^(id _Nullable title, NSError * _Nullable error) {

        if (ValidStr(title)) {

            self.title = title;

        } else {

            self.title = @"";
        }

    }];

2.在第一种方法获取不到title的时候，添加KVO监听方法，用来获取webView的title

// 添加进度监听
[_webView addObserver:self forKeyPath:@"title" options:NSKeyValueObservingOptionNew context:NULL];

#pragma mark KVO 实现方法
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSKeyValueChangeKey,id> *)change context:(void *)context {
    
    if ([keyPath isEqualToString:@"title"]) {
        
        if (object == self.webView) {
            
            self.title = self.webView.title;

        } else {
            
            [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
        }
    }
}