IOS网络第七天WebView-02WebView和网页的交互2，删除大众点评多余文字，加上蒙版进度

#import "HMViewController.h"

@interface HMViewController () <UIWebViewDelegate>
@property (nonatomic, weak) UIActivityIndicatorView *loadingView;
@end

@implementation HMViewController

/**
test.html存在于服务器，里面的html和js代码，我们是无法修改的

如果test.html显示在手机端，把那个ul去掉

*/

- (void)viewDidLoad
{
[super viewDidLoad];
// 1.webView
UIWebView *webView = [[UIWebView alloc] init];
webView.frame = self.view.bounds;
webView.delegate = self;
// 伸缩页面至填充整个webView
webView.scalesPageToFit = YES;
// 隐藏scrollView
webView.scrollView.hidden = YES;
[self.view addSubview:webView];

// 2.加载网页
NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://m.dianping.com/tuan/deal/5501525"]];
[webView loadRequest:request];

// 3.创建圈圈
UIActivityIndicatorView *loadingView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
[loadingView startAnimating];
loadingView.center = CGPointMake(160, 240);
[self.view addSubview:loadingView];
self.loadingView = loadingView;
}

// OC -> JS
// 在OC中调用JS

#pragma mark - UIWebViewDelegate
- (void)webViewDidFinishLoad:(UIWebView *)webView
{
// 执行JS代码，将大众点评网页里面的多余的节点删掉
//    var html =  document.body.innerHTML;
//    NSString *html = [webView stringByEvaluatingJavaScriptFromString:@"document.body.innerHTML;"];
//    NSLog(@"%@", html);

NSMutableString *js1 = [NSMutableString string];
// 0.删除顶部的导航条
[js1 appendString:@"var header = document.getElementsByTagName('header')[0];"];
[js1 appendString:@"header.parentNode.removeChild(header);"];

// 1.删除底部的链接
[js1 appendString:@"var footer = document.getElementsByTagName('footer')[0];"];
[js1 appendString:@"footer.parentNode.removeChild(footer);"];
[webView stringByEvaluatingJavaScriptFromString:js1];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.25 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
NSMutableString *js2 = [NSMutableString string];
// 2.删除浮动的广告
[js2 appendString:@"var list = document.body.childNodes;"];
[js2 appendString:@"var len = list.length;"];
[js2 appendString:@"var banner = list[len - 1];"];
[js2 appendString:@"banner.parentNode.removeChild(banner);"];
[webView stringByEvaluatingJavaScriptFromString:js2];

// 显示scrollView
webView.scrollView.hidden = NO;

// 删除圈圈
[self.loadingView removeFromSuperview];
});
}

@end