Quick and dirty filtering in JavaScript ... inefficient!

crap_filter.js

var previous_result = '';
// listen to an input ...
$('#filter-input').live('keyup', function(evt) {
    var filtering_by = $(this).val().toLowerCase();
    if (previous_result === filtering_by) {
        return;
    }
    previous_result = filtering_by;
    // eg: labels, list items, whatever.
    var possibles = $('#nodes-to-filter'); 
    possibles.each(function(evt) {
        var $this = $(this);
        var text = $this.text().toLowerCase();
        // hide or show the parent element.
        if (text.indexOf(filtering_by) !== -1) {
            $this.parent().show();
        } else {
            $this.parent().hide();
        }
    });
});