WKWebView加载HTML标签字体问题

       WKPreferences *preferences = [[WKPreferences alloc] init];

        preferences.minimumFontSize = 15.0f;



        NSMutableString *javascript = [NSMutableString string];

        [javascript appendString:@"document.documentElement.style.webkitTouchCallout='none';"]; //禁止长按

        [javascript appendString:@"document.documentElement.style.webkitUserSelect='none';"]; //禁止选择

    

        WKUserScript *noneSelectScript = [[WKUserScript alloc] initWithSource:javascript injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];

         //通过WKUserScript注入JavaScript脚本和WKPreferences设置字体大小

        NSString *jScript = @"var meta = document.createElement('meta'); meta.setAttribute('name', 'viewport'); meta.setAttribute('content', 'width=device-width'); document.getElementsByTagName('head')[0].appendChild(meta);";

        //注入

        WKUserScript *wkUScript = [[WKUserScript alloc] initWithSource:jScript injectionTime:WKUserScriptInjectionTimeAtDocumentEnd forMainFrameOnly:YES];

        WKUserContentController *userContentController = [[WKUserContentController alloc] init];

        [userContentController addUserScript:noneSelectScript];

        [userContentController addUserScript:wkUScript];

        

        WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];

        config.preferences = preferences;

        config.userContentController = userContentController;

        

        _contentWKWebView = [[WKWebView alloc] initWithFrame:CGRectZeroconfiguration:config];

        _contentWKWebView.navigationDelegate = self;

        _contentWKWebView.scrollView.alwaysBounceVertical = NO; //内容少于webView高度的时候不垂直滚动