title: Filter search query
body: <p>I have a table with the columns City and ZoneCode. I have a dropdown list where I can select just one City or all. And another dropdownlist for the ZoneCode. Basically they are filters that only filter if I select a value from the dropdown lists.</p>
  
  <p>Is there any recommended technique to do this?</p>
  
  <p>edit: this table is only an example. </p>
  
  <p>Thank you</p>