$(function() {
	
  var time = 500;

  $('#jump-nav a[href^=#]').click(function() {
    var target = $(this.hash);
    if (!target.length) return ;
    var targetY = target.offset().top;
    $('html,body').animate({scrollTop: targetY}, time, 'swing');
    window.history.pushState(null, null, this.hash);
    return false;
  });

var img_dev;
function win_wid(){
  win_w = $(window).width();
  if(win_w <= 721 && img_dev != 'smp'){
    $('.img_chg').css({'opacity': '0'});
    $('.img_chg').each(function(){
      $(this).attr('src', $(this).attr('src')+'_s');
      $(this).load(function(){
        $(this).css({'opacity': '1'});
      });
    });
    img_dev = 'smp';
  }else if(win_w > 720 && img_dev != 'pc'){
    $('.img_chg').each(function(){
        if($(this).attr('src').endsWith('_s')){
          $(this).attr('src', $(this).attr('src').slice( 0, -2 ));
        }
    });
    img_dev = 'pc';
  }
}
win_wid();
$(window).resize(function(){
  win_wid();
});

 
 
});