#! /bin/sh /usr/share/dpatch/dpatch-run
## ie_innerhtml_backticks.dpatch by Francois Marier <francois@debian.org>
##
## All lines beginning with `## DP:' are a description of the patch.
## DP: Fix Internet Explorer innerHTML bug (0dd9e4faf43e69ef05d30902317b09597eb14291)

@DPATCH@
--- a/htdocs/lib/htmlpurifier/HTMLPurifier/Generator.php
+++ b/htdocs/lib/htmlpurifier/HTMLPurifier/Generator.php
@@ -192,6 +192,35 @@ class HTMLPurifier_Generator
                     continue;
                 }
             }
+            // Workaround for Internet Explorer innerHTML bug.
+            // Essentially, Internet Explorer, when calculating
+            // innerHTML, omits quotes if there are no instances of
+            // angled brackets, quotes or spaces.  However, when parsing
+            // HTML (for example, when you assign to innerHTML), it
+            // treats backticks as quotes.  Thus,
+            //      <img alt="``" />
+            // becomes
+            //      <img alt=`` />
+            // becomes
+            //      <img alt='' />
+            // Fortunately, all we need to do is trigger an appropriate
+            // quoting style, which we do by adding an extra space.
+            // This also is consistent with the W3C spec, which states
+            // that user agents may ignore leading or trailing
+            // whitespace (in fact, most don't, at least for attributes
+            // like alt, but an extra space at the end is barely
+            // noticeable).  Still, we have a configuration knob for
+            // this, since this transformation is not necesary if you
+            // don't process user input with innerHTML or you don't plan
+            // on supporting Internet Explorer.
+            if (strpos($value, '`') !== false) {
+                // check if correct quoting style would not already be
+                // triggered
+                if (strcspn($value, '"\' <>') === strlen($value)) {
+                    // protect!
+                    $value .= ' ';
+                }
+            }
             $html .= $key.'="'.$this->escape($value).'" ';
         }
         return rtrim($html);