// Bind an event handler to the "click" JavaScript event
$('#clear').click(function(){
    // Selects all elements of type text and clear all
    $('#parent > input:text:not(".ignore")').val('');   
      // For excluding Multiple inputs 
      $("input:text:not('#objective_time_period, #subjective_time_period')").val('');
});

Example : http://jsfiddle.net/3zVyv/1/