setInterval 执行错误

var autoService = setInterval( autoService, serviceSpeed );
    $(".service_smallNav li").click(
        function (args) {
            clearInterval(autoService);
            var index = $(this).index(); 
            var Slist = $(".service_Content li");
            var smallSlist = $(".service_smallNav li");
            smallSlist.removeClass("current");
            smallSlist.eq(index).addClass("current"); 
            Slist.hide();
            Slist.eq(index).fadeIn();
            //无法执行
            //autoService = setInterval( autoService, serviceSpeed );
        } 
    ); 

javascript?
[解决办法]
alert(123) //测一下函数有没有调用到
//autoService = setInterval( autoService, serviceSpeed );