function search_input(element_id,set_focus) {
  
  var si = this;
  var input_field = $(element_id);
  var default_input = 'Enter ';
  
  si.init = function() {
    //set focus to search input field; select field contents
    if (set_focus) {
      focus_select();
    }
    input_field.keypress(function(){
      clear_input();
    }); 
    input_field.click(function(){
      clear_input();
    });
  };
  
  //clear input contents on keypress or click in field, but only if default value is set
  si.clear_input = function() {
    if (input_field.val().indexOf(default_input) == 0) {
      input_field.val('');
    }
  };
  si.focus_select = function() {
    input_field.focus();
    input_field.select();
  };
  
  si.init();
  return si;
  
}