需求：

調(diào)起網(wǎng)頁，監(jiān)聽返回的點擊事件，返回上一層

Snip20170612_5.png

1. 寫個類，并需要導入#import <JavaScriptCore/JavaScriptCore.h>，所需代碼不上100行

- (void)viewDidLoad{
    [super viewDidLoad];
    UIWebView *web =[[UIWebView alloc]initWithFrame:CGRectMake(0,-0, LYScreen_Width, LYScreen_Height-64)];
    web.delegate = self;
    [self.view addSubview:web];
    NSURLRequest *httpRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:LYlytUrl]];
    [web loadRequest:httpRequest];

}
- (void)webViewDidFinishLoad:(UIWebView *)webView{
    
    JSContext *jsContext = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
       LYWeakSelf;
        /// 關聯(lián)打印異常
        jsContext.exceptionHandler = ^(JSContext *context, JSValue *exceptionValue) {
            context.exception = exceptionValue;
        };
        jsContext[@"closeTopicView"] = ^{           dispatch_async(dispatch_get_main_queue(), ^{
            [weakSelf.navigationController popViewControllerAnimated:YES];
            });
        };
}

2.在其需要處導入上面寫的類名，然后進行初始化，push過去即可。