-(void)webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigationAction *)navigationAction decisionHandler:(void (^)(WKNavigationActionPolicy))decisionHandler{
   
    if(webView != self.wkWebView) {
        decisionHandler(WKNavigationActionPolicyAllow);
        return;
    }
    NSURL  * url = navigationAction.request.URL;
    UIApplication *app = [UIApplication sharedApplication];
    
//    appstore
    if ([url.absoluteString containsString:@"itunes.apple.com"]) {
        if ([app canOpenURL:url]){
            
            [app openURL:url options:@{} completionHandler:^(BOOL success) {
                
            }];
            decisionHandler(WKNavigationActionPolicyCancel);
            return;
        }
    }
    if (!navigationAction.targetFrame.isMainFrame) {
        [self.wkWebView loadRequest:navigationAction.request];
    }
//    appstore的外的包  慎用 itms-services ----審核會被拒
    if ([url.absoluteString containsString:@"itms-services://"]) {
        [app openURL:url options:@{} completionHandler:^(BOOL success) {
            
        }];
        decisionHandler(WKNavigationActionPolicyCancel);
        return;
    }
    decisionHandler(WKNavigationActionPolicyAllow);
}