https://www.enetshop.jp/common/js/inc_yf.js

1function include(filename, afterfunc) {
2
3  include.seq = (include.seq)? include.seq + 1: 1;
4
5  var id = new Date().getTime() + "-" + include.seq;
6  var inc = document.createElement("iframe");
7
8  inc.id = "inc-" + id;
9  inc.src = filename;
10  inc.style.display = "none";
11  document.write("<span id=\"" + id + "\"></span>");
12    
13  var incfunc = function() {
14    
15    var s = (function() {
16      var suffix = (n = filename.lastIndexOf(".")) >= 0 ? filename.substring(n): "default";
17      if (suffix == ".html") return inc.contentWindow.document.body.innerHTML;
18      if (suffix == ".txt") return inc.contentWindow.document.body.firstChild.innerHTML;
19      if (suffix == "default") return inc.contentWindow.document.body.innerHTML;
20    })();
21
22    var span = document.getElementById(id);
23
24    var insertBeforeHTML = function(htmlStr, refNode) {
25      if (document.createRange) {
26        var range = document.createRange();
27        range.setStartBefore(refNode);
28        refNode.parentNode.insertBefore(range.createContextualFragment(htmlStr), refNode);
29      } else {
30        refNode.insertAdjacentHTML('BeforeBegin', htmlStr);
31      }
32    };
33
34    insertBeforeHTML(s.split("&gt;").join(">").split("&lt;").join("<"), span);
35    document.body.removeChild(inc);
36    span.parentNode.removeChild(span);
37    if (afterfunc) afterfunc();
38  };
39
40  if (window.attachEvent) {
41    window.attachEvent('onload', 
42      function() {
43        document.body.appendChild(inc); 
44        inc.onreadystatechange = function() { if (this.readyState == "complete") incfunc(); };
45      });
46  }
47  else {
48    document.body.appendChild(inc);
49    inc.onload = incfunc;
50  }
51}