首先来看下UIWebView的做法:

UIWebView *webView = [[UIWebViewalloc]initWithFrame:CGRectMake(0,0,WIDTH,0)];

webView.delegate =self;
[self.viewaddSubview:webView];

[webView loadHTMLString:html/*html内容*/ baseURL:nil];

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

    //获取页面高度，并重置webview的frame
    CGFloat documentHeight = [[webViewstringByEvaluatingJavaScriptFromString:@"document.getElementById(\"content\").offsetHeight;"]floatValue];
    CGRect frame = webView.frame;
    frame.size.height = documentHeight;
    webView.frame = frame;
}

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType {
    
    NSString* strRequest = request.URL.absoluteString;
    
    if([strRequestisEqualToString:@"about:blank"]) {//主页面加载内容
        returnYES;//允许跳转
    } else {//截获页面里面的链接点击
        //do something you want
        returnNO;//不允许跳转
    }
}

在来对应看下WKWebView:

WKWebView   *wkWebview = [[WKWebView alloc] initWithFrame:CGRectMake(0, 0, WIDTH, 0)];
wkWebview.navigationDelegate = self;
[self.view wkWebview];

[wkWebview loadHTMLString:html/*html内容*/ baseURL:nil];

- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecifiedWKNavigation *)navigation {
    [webView evaluateJavaScript:@"document.getElementById(\"content\").offsetHeight;"completionHandler:^(id_Nullableresult,NSError *_Nullable error) {
//获取页面高度，并重置webview的frame
        CGFloat documentHeight = [resultdoubleValue];
        CGRect frame = webView.frame;
        frame.size.height = documentHeight;
        webView.frame = frame;
    }];
}

// 类似 UIWebView的 -webView: shouldStartLoadWithRequest: navigationType:
- (void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void(^)(WKNavigationActionPolicy))decisionHandler {
    
    NSString *strRequest = [navigationAction.request.URL.absoluteStringstringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
    if([strRequestisEqualToString:@"about:blank"]) {//主页面加载内容
        decisionHandler(WKNavigationActionPolicyAllow);//允许跳转
    } else {//截获页面里面的链接点击
        //do something you want
        decisionHandler(WKNavigationActionPolicyCancel);//不允许跳转
    }
}