function bigImg(obj) {
  var path = $(obj).attr('data-url');
  $("#bigImg").attr('src', path);
  var image = new Image();
  image.src = path;
  image.onload = function () {
    var windowW = $(window).width();
    var windowH = $(window).height();
    var realWidth = image.width;
    var realHeight = image.height;
    var imgWidth, imgHeight;
    var scale = 0.8;
    if (realHeight > windowH * scale) {
      imgHeight = windowH * scale;
      imgWidth = imgHeight / realHeight * realWidth;
      if (imgWidth > windowW * scale) {
        imgWidth = windowW * scale;
      }
    } else if (realWidth > windowW * scale) {
      imgWidth = windowW * scale;
      imgHeight = imgWidth / realWidth * realHeight;
    } else {
      imgWidth = realWidth;
      imgHeight = realHeight;
    }
    $(".mengceng").css("display", "block");
    $(".show-bigImg").css("width", imgWidth);
    var w = (windowW - imgWidth) / 2;
    var h = (windowH - imgHeight) / 2;
    $(".show-bigImg").css({ "top": h, "left": w });
  }
}

$(".mengceng").click(function () {
  $("#bigImg").attr('src', "");
  $(".mengceng").css("display", "none");
});