ddns script - is it possible to ... ?

RouterOS Scripting
1

Hi,
Is it possible to use below script and do not set interface name which I want to use and let router use default wan which is currently active ?
I am asking becuse I have a plan to make ddns domain work under two wan connection.
1wan= DSL, 2wan=3g network.

For 1wan I have static IP, for 2wan I have dynamic IP assigned from 3g network.


Currently I am using this script on my router v.6.23

log info ""

:local ipadd [/ip address get [find interface=ether1-gateway ] address ]

:local NOIPUser ""
:local NOIPPass ""
:local NOIPDomain ""

:local IpCurrent ("$ipadd" .\ "/32");
#:log info "$IpCurrent";

:for i from=( [:len $IpCurrent] - 1) to=0 do={ 
  :if ( [:pick $IpCurrent $i] = "/") do={ 
    :local NewIP [:pick $IpCurrent 0 $i];
#:log info "$NewIP";
    :if ([:resolve $NOIPDomain] != $NewIP) do={
      /tool fetch mode=http user=$NOIPUser password=$NOIPPass url="http://dynupdate.no-ip.com/nic/update\3Fhostname=$NOIPDomain&myip=$NewIP" keep-result=no
      :log info "NO-IP Update: $NOIPDomain - $NewIP"
     }
   } 
}
log info ""