ios - Multiple accounts login in different webView in same app -

how can login many accounts of same site in different webview. example have tab bar controller contains 3 view controllers , each view controllers contain webview. , example embed stackoverflow url webview in every class. how user can login different accounts @ same time using these 3 webview? i've tried login 1 user @ time. can 1 please tell me how possible in (swift or objective-c)?? thanks

class firstviewcontroller: uiviewcontroller , uiwebviewdelegate{      @iboutlet weak var webview: uiwebview!     @iboutlet weak var activityindicator: uiactivityindicatorview!      override func viewdidload() {         webview.delegate = self         let requesturl = nsurl(string: "http://stackoverflow.com")         let request = nsurlrequest(url: requesturl!)         activityindicator.hideswhenstopped = true         activityindicator.startanimating()         webview.loadrequest(request)      }        func webviewdidfinishload(webview: uiwebview) {         activityindicator.stopanimating()     }  }  class secondviewcontroller: uiviewcontroller, uiwebviewdelegate{      @iboutlet weak var webview: uiwebview!     @iboutlet weak var activityindicator: uiactivityindicatorview!      override func viewdidload() {         webview.delegate = self         let requesturl = nsurl(string: "http://stackoverflow.com")         let request = nsurlrequest(url: requesturl!)         activityindicator.hideswhenstopped = true         activityindicator.startanimating()         webview.loadrequest(request)      }         func webviewdidfinishload(webview: uiwebview) {         activityindicator.stopanimating()     }   }