var slide_num = 0;
var image_count = 7;
$(function(){
    $('.photo_thumbs ul li').click(function(){
        $('.photo_thumbs ul li').removeClass('on');
        $(this).addClass('on');
        var img_num = $(this).find('img').attr('src').split('center_img')[1].split('.jpg')[0];
        $('#big_img').attr('src','/new_img/sub/sub1/'+img_num+'.jpg');
    });

    $('.arrow_left').click(function(){
        if(slide_num > 0){
            $( "#slider_box" ).animate({
                marginLeft: "+=146"
            }, 250, function() {slide_num--});
        }else{
            alert('첫번째 이미지 입니다');
        }
    });

    $('.arrow_right').click(function(){
        if(slide_num < image_count){
            $( "#slider_box" ).animate({
                marginLeft: "-=146"
            }, 250, function() {slide_num++});
        }else{
            alert('마지막 이미지 입니다');
        }
    });

});