$(document).ready(function(){
  $('#filter').search('#items tr'); 
});

$.fn.search = function(searchElements) {
  $(this).keyup(function(){ 
    var searchString = $(this).val(); 
    
    if (searchString.length > 0){  
      $(searchElements).hide();
      $(searchElements+':contains(' +searchString+ ')').show(); 
    }
    else {
      $(searchElements).show();
    } 
  });  
};