javascript ignore case filter

gistfile1.js

    // custom css expression for a case-insensitive contains()
    $.expr[':'].Contains = function(a, i, m) {
        return (a.textContent || a.innerText || "").toLowerCase().indexOf(m[3].toLowerCase()) >= 0;
    };

    $(".search-box").keyup(function(e) {
        //get current value
        var that = $(this).val();

        if (that.length > 0) { //something exists

            $(".listofitems .item")
            .hide(); //hide all those that does not contain the input

            $(".listofitems .item:Contains(" + that + ")")
            .show(); //show all that contain the input

        }
        else {
            $(".listofitems .item")
            .show(); //nothing entered so show all items by default
        }
    });

$matches = $(list).find('a:Contains(' + filter + ')').parent();
$('li', list).not($matches).slideUp();
$matches.slideDown();