获取并修改UIWebView的userAgent

OC修改：

NSString*userAgent = [[[UIWebViewalloc]init] stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];

NSString*newUagent = [NSStringstringWithFormat:@"%@ app/iOS",userAgent];

NSDictionary*dictionary = @{@"UserAgent":newUagent}; [[NSUserDefaultsstandardUserDefaults] registerDefaults:dictionary];

swift修改：

let oldAgent = UIWebView().stringByEvaluatingJavaScript(from: "navigator.userAgent")

let newAgent = oldAgent! +"app/iOS"

UserDefaults.standard.register(defaults: ["UserAgent": newAgent])

修改方法需放在Appdelegate的 didFinishLaunchingWithOptions 方法中实现才有效果