response from server json doesn't make my condition true

Why is this my response from the server doesn't make my condition true in returning success.

Here is my simple code:

Here i have a server side which is returning this code after a request from client:

$response['success']='true';
header('Content-Type', 'application/json');
echo json_encode($response);

In my script, I have something like this which I have a problem and it's not making my if condition into true

if(response.success === 'true') {
    $('.spnner_here').html('');                                     
    $(":submit").attr("disabled", false);
    swal('Successfully save', {
        icon: "success",
    });                     
    window.location = baseurl+'user_child_info';
}else {

}