code: function updateExpression() {
    // Default highlighter will not highlight anything
    var nullHighlighter = function(item) { return false; }
  
    var input = $('.expression');
    var expression = input.val();
  
    var highlighter;
  
    if (!expression) {
      // No expression specified. Don't highlight anything.
      highlighter = nullHighlighter;
      input.css('background-color', '#fff');
    } else {
      try {
        // Build highlighter from user's expression
        highlighter = compileExpression(expression); // <-- Filtrex!
        input.css('background-color', '#dfd');
      } catch (e) {
        // Failed to parse expression. Don't highlight anything.
        highlighter = nullHighlighter;
        input.css('background-color', '#fdd');
      }
    }
  
    highlightRows(highlighter);
  }
docs: When user entered expression changes, attempt to parse it
  and apply highlights to rows that match filter.