var imglist = new Array(
      "top_img34.jpg",
      "top_img33.jpg",
      "top_img32.jpg",
      "top_img31.jpg",
      "top_img30.jpg",
      "top_img29.jpg",
      "top_img28.jpg",
      "top_img27.jpg",
      "top_img25.jpg",
      "top_img24.jpg",
      "top_img23.jpg",
      "top_img21.jpg",
      "top_img20.jpg",
      "top_img19.jpg",
      "top_img18.jpg",
      "top_img17.jpg",
      "top_img16.jpg",
      "top_img15.jpg",
      "top_img14.jpg",
      "top_img13.jpg",
      "top_img12.jpg",
      "top_img11.jpg",
      "top_img10.jpg",
      "top_img9.jpg",
      "top_img7.jpg",
      "top_img6.jpg",
      "top_img5.jpg",
      "top_img4.jpg",
      "top_img3.jpg",
      "top_img2.jpg",
      "top_img1.jpg"
   );
   var selectnum = Math.floor((Math.random() * 100)) % imglist.length;
   var output = "<img src='randam_image/" + imglist[selectnum] + "' width='700' alt='シンプルでモダンな住宅の施工事例' />";
   document.write(output);