IOS網絡第七天WebView-02WebView和網頁的交互2，刪除大衆點評多餘文字，加上蒙版進度

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#import "HMViewController.h"

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

@implementation HMViewController

/**
 test.html存在於服務器，裏面的html和js代碼，咱們是沒法修改的

 若是test.html顯示在手機端，把那個ul去掉
 
 */

- (void)viewDidLoad
{
    [super viewDidLoad];
    // 1.webView
    UIWebView *webView = [[UIWebView alloc] init];
    webView.frame = self.view.bounds;
    webView.delegate = self;
    // 伸縮頁面至填充整個webView
    webView.scalesPageToFit = YES;
    // 隱藏scrollView
    webView.scrollView.hidden = YES;
    [self.view addSubview:webView];
    
    // 2.加載網頁
    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://m.dianping.com/tuan/deal/5501525"]];
    [webView loadRequest:request];
    
    // 3.建立圈圈
    UIActivityIndicatorView *loadingView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
    [loadingView startAnimating];
    loadingView.center = CGPointMake(160, 240);
    [self.view addSubview:loadingView];
    self.loadingView = loadingView;
}

// OC -> JS
// 在OC中調用JS

#pragma mark - UIWebViewDelegate
- (void)webViewDidFinishLoad:(UIWebView *)webView
{
    // 執行JS代碼，將大衆點評網頁裏面的多餘的節點刪掉
//    var html =  document.body.innerHTML;
//    NSString *html = [webView stringByEvaluatingJavaScriptFromString:@"document.body.innerHTML;"];
//    NSLog(@"%@", html);
    
    NSMutableString *js1 = [NSMutableString string];
    // 0.刪除頂部的導航條
    [js1 appendString:@"var header = document.getElementsByTagName('header')[0];"];
    [js1 appendString:@"header.parentNode.removeChild(header);"];
    
    // 1.刪除底部的連接
    [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.刪除浮動的廣告
        [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];
        
        // 顯示scrollView
        webView.scrollView.hidden = NO;
        
        // 刪除圈圈
        [self.loadingView removeFromSuperview];
    });
}

@end