//返回和关闭按钮

@property (nonatomic, weak) UIButton * backItem;  
@property (nonatomic, weak) UIButton * closeItem;  

- (void)initNavigationView{  
  
UIView * backView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 100, 44)];  
UIButton * backItem = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 56, 44)];  
[backItem setImage:[UIImage imageNamed:@"popImage"] forState:UIControlStateNormal];  
[backItem setImageEdgeInsets:UIEdgeInsetsMake(0, -15, 0, 0)];  
[backItem setTitle:@"返回" forState:UIControlStateNormal];  
backItem.titleLabel.font = [UIFont systemFontOfSize:15];  
[backItem setTitleEdgeInsets:UIEdgeInsetsMake(0, -15, 0, 0)];  
[backItem setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];  
[backItem addTarget:self action:@selector(clickedBackItem:) forControlEvents:UIControlEventTouchUpInside];  
self.backItem = backItem;  
[backView addSubview:backItem];  
  
UIButton * closeItem = [[UIButton alloc]initWithFrame:CGRectMake(52, 0, 44, 44)];  
[closeItem setTitle:@"关闭" forState:UIControlStateNormal];  
[closeItem setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];  
[closeItem addTarget:self action:@selector(clickedCloseItem:) forControlEvents:UIControlEventTouchUpInside];  
closeItem.titleLabel.font = [UIFont systemFontOfSize:15];  
closeItem.hidden = YES;  
self.closeItem = closeItem;  
[backView addSubview:closeItem];  
UIBarButtonItem * leftItemBar = [[UIBarButtonItem alloc]initWithCustomView:backView];  
self.navigationItem.leftBarButtonItem = leftItemBar;  

}

pragma mark - 返回

- (void)clickedBackItem:(UIBarButtonItem *)btn{  
UIWebView * webView = [self.view viewWithTag:100];  
if (webView.canGoBack) {  
    [webView goBack];  
    self.closeItem.hidden = NO;  
}else{  
    [self clickedCloseItem:nil];  
}  
}  

pragma mark - 关闭

- (void)clickedCloseItem:(UIButton *)btn{  
[self.navigationController popViewControllerAnimated:YES];  
}