WKWebView从入门到趟坑http://www.jianshu.com/p/90a90bd13aac
UIWebView从 iOS2 就有，iOS8 以后，苹果推出了新框架 WebKit，提供了替换 UIWebView 的组件 WKWebView。
WKWebView的性能比UIWebView好

#import "ViewController.h"
#import <WebKit/WebKit.h>
@interface ViewController ()<WKNavigationDelegate>

@property (nonatomic,strong) WKWebView *wkWebView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    _wkWebView = [[WKWebView alloc] initWithFrame:self.view.bounds];
    [_wkWebView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.baidu.com"]]];
    _wkWebView.navigationDelegate= self;
    [self.view addSubview:_wkWebView];
}

#pragma WKNavigationDelegate
// 页面开始加载时调用
- (void)webView:(WKWebView *)webView didStartProvisionalNavigation:(WKNavigation *)navigation{
    NSLog(@"页面开始加载时调用");
}
// 当内容开始返回时调用
- (void)webView:(WKWebView *)webView didCommitNavigation:(WKNavigation *)navigation{
    NSLog(@"当内容开始返回时调用");
}
// 页面加载完成之后调用
- (void)webView:(WKWebView *)webView didFinishNavigation:(WKNavigation *)navigation{
    NSLog(@"页面加载完成之后调用");
}
// 页面加载失败时调用
- (void)webView:(WKWebView *)webView didFailProvisionalNavigation:(WKNavigation *)navigation{
    NSLog(@"页面加载失败时调用");
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


@end