javascript - firebase-ui for email verification -

i've set firebase email/password authentication using firebase-ui.

 var uiconfig = {         signinsuccessurl: '<?php echo $url; ?>',         signinoptions: [             // leave lines providers want offer users.             firebase.auth.googleauthprovider.provider_id,             firebase.auth.facebookauthprovider.provider_id,             firebase.auth.emailauthprovider.provider_id         ],         // terms of service url.         tosurl: '<your-tos-url>'     };      // initialize firebaseui widget using firebase.     var ui = new firebaseui.auth.authui(firebase.auth());     // start method wait until dom loaded.     ui.start('#firebaseui-auth-container', uiconfig); 

but security reasons want user confirm her/his email.but fromthe above code doesn't send verfication mail user. i've used following method send verification mail user if he/she not verified his/her account mail.

firebase.auth().onauthstatechanged(function(user) {     if (user && user.uid != currentuid) {         if (firebase.auth().currentuser.emailverified) {             currentuid = user.uid;          else {         //---- here send email             firebase.auth().currentuser.sendemailverification();             } 

but when used code sends multiple verification mails same account. means method runs each time user reload page. greatful if me identify whether verification mail sent or not specific user using firebase.