var base_convert = function(number, initial_base, change_base) {  
       if ((initial_base && change_base) <2 || (initial_base && change_base)>36)  
        return 'Base between 2 and 36';  
         
        return parseInt(number + '', initial_base)  
        .toString(change_base);  
    }  
      
    console.log(base_convert('E164',16,8));  
    console.log(base_convert(1000,2,8));