1.签协议

@interface ViewController ()<UIWebViewDelegate>

2.创建webView

 _webView = [[UIWebView alloc]initWithFrame:CGRectMake(0, 20, 375, 647)];
//加载网页:
[_webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.baidu.com"]]];
_webView.delegate = self;
[self.view addSubview:_webView];

pragma mark -- 开始加载

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

NSLog(@"开始加载");

}

pragma mark -- 结束加载

-(void)webViewDidFinishLoad:(UIWebView *)webView{
NSLog(@"结束加载");

}