$(document).ready( function(){
$('.service1, .service2, .service3').hide();
$('.service1').show();
$('#services-main').change(function(){

var type_val = $(this).val();
switch(type_val){
case '1':
$('.service1, .service2, .service3').hide();
$('.service1').fadeIn();
break;
case '2':
$('.service1, .service2, .service3').hide();
$('.service2').fadeIn();
break;
case '3':
$('.service1, .service2, .service3').hide();
$('.service3').fadeIn();
break;
}
});
});