Why doesn’t IE7 copy blocks to the clipboard correctly?

It seems that this is a known bug for IE6 and prettify.js has a workaround for it. Specifically it replaces the BR tags with ‘\r\n’.

By modifying the check to allow for IE6 or 7 then the cut-and-paste will work correctly from IE7, but it will render with a newline followed by a space. By checking for IE7 and providing just a ‘\r’ instead of a ‘\r\n’ it will continue to cut-and-paste and render correctly.

Add this code to prettify.js:

function _pr_isIE7() {
  var isIE7 = navigator && navigator.userAgent &&
       /\bMSIE 7\./.test(navigator.userAgent);
  _pr_isIE7 = function () { return isIE7; };
  return isIE7;
}

and then modify the prettyPrint function as follows:

   function prettyPrint(opt_whenDone) {
     var isIE6 = _pr_isIE6();
+    var isIE7 = _pr_isIE7();

…

-        if (isIE6 && cs.tagName === 'PRE') {
+        if ((isIE6 || isIE7) && cs.tagName === 'PRE') {
          var lineBreaks = cs.getElementsByTagName('br');
+         var newline;
+         if (isIE6) {
+           newline="\r\n";
+         } else {
+           newline="\r";
+         }
          for (var j = lineBreaks.length; --j >= 0;) {
            var lineBreak = lineBreaks[j];
            lineBreak.parentNode.replaceChild(
-               document.createTextNode('\r\n'), lineBreak);
+               document.createTextNode(newline), lineBreak);
          }

You can see a working example here.

Note: I haven’t tested the original workaround in IE6, so I’m guessing it renders without the space caused by the ‘\n’ that is seen in IE7, otherwise the fix is simpler.