在从php成功响应后，如何将用户重定向到ajax中的另一个页面

i have a javascript function which works fine. it returns all the errors messages from the php file to a span of ID resto very fine. i need if php file returns a specific massege (you have sucessfuly regestered!check your email to activated your account) the user should be redirected to another page. can any one help please

        function divsub(){
    var firstname= document.getElementById('first_name').value;
    var lastname= document.getElementById('lastname').value;
    var username= document.getElementById('username').value;
    var email= document.getElementById('email').value;
    var emailconfirm= document.getElementById('confirmemail').value;
    var pass= document.getElementById('pass_id').value;
    var passconfrim= document.getElementById('confirmpassword').value;
    var phone= document.getElementById('phone').value;
    var datastring = 'first_name='+firstname+'&lastname='+lastname+'&username='+username+'&email='+email+'&confirmemail='+emailconfirm+'&pass_id='+pass+'&confirmpassword='+passconfrim+'&phone='+phone;
    $.ajax({

        type:"POST",
        url:"regestration.php",
        data:datastring,
        cache:false,
        success:function(html){
                if(html === "you have sucessfuly regestered!check your email to activated your account.") {

                    var ffirstname= document.getElementById('first_name').value;
                    var eemail= document.getElementById('email').value;

                  location.href = "rregsuccess.php?first_name="+ffirstname+"&email"+eemail;


                }
                else{
                    $('#resto').html(html);
        //  window.location.href = "regsuccess.php";
                }

        }

    });
    return false;
}

// after ajax success
// Redirect user to url
window.open("https://google.com","_self");