File upload extension made with jQuery

/*
*jquery.ajaxUpload.js
*/jQuery.extend({    ajaxFileUpload: function(s) {
        s = jQuery.extend({}, jQuery.ajaxSettings, s);
        s.type = "POST";        var f = new FormData();        for (var k in s.data) {
            f.append(k, s.data[k]);
        }        if (s.fileElementId) {            if (!jQuery("#" + s.fileElementId).attr("multiple")) {
                f.append(s.fileElementId, jQuery("#" + s.fileElementId).get(0).files[0]);
            } else {                var fs = jQuery("#" + s.fileElementId).get(0).files;                for (var i = 0; i < fs.length; i++) {
                    f.append(s.fileElementId + "[]", fs[i]);
                }
            }
        }
        s.processData = s.contentType = false;
        s.data = f;
        jQuery.ajax(s);
    }
});