加载网页的视图
self.webView = [[UIWebView alloc] initWithFrame:self.view.frame];
[self.view addSubview:self.webView];
//创建url对象
NSURL *url = [NSURL URLWithString:@"http://www.jianshu.com"];
//创建request
NSURLRequest *request = [NSURLRequest requestWithURL:url];
//加载网页
[self.webView loadRequest:request];
