diff --git a/lib/configonlylib.php b/lib/configonlylib.php
index 9ceee1e58fd..791d2461695 100644
--- a/lib/configonlylib.php
+++ b/lib/configonlylib.php
@@ -123,10 +123,15 @@ function min_get_slash_argument() {
 
     $relativepath = '';
 
-    if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
+    if (!empty($_GET['file']) and strpos($_GET['file'], '/') === 0) {
+        // server is using url rewriting, most probably IIS
+        return $_GET['file'];
+
+    } else if (stripos($_SERVER['SERVER_SOFTWARE'], 'iis') !== false) {
         if (isset($_SERVER['PATH_INFO']) and $_SERVER['PATH_INFO'] !== '') {
             $relativepath = urldecode($_SERVER['PATH_INFO']);
         }
+
     } else {
         if (isset($_SERVER['PATH_INFO'])) {
             $relativepath = $_SERVER['PATH_INFO'];
diff --git a/lib/javascript-static.js b/lib/javascript-static.js
index ae4068b7b2d..19c584f9476 100644
--- a/lib/javascript-static.js
+++ b/lib/javascript-static.js
@@ -1793,7 +1793,7 @@ M.util.load_flowplayer = function() {
         if (M.cfg.jsrev == -10) {
             var jsurl = M.cfg.wwwroot + '/lib/flowplayer/flowplayer-3.2.8.min.js';
         } else {
-            var jsurl = M.cfg.wwwroot + '/lib/javascript.php?file=/lib/flowplayer/flowplayer-3.2.8.min.js&rev=' + M.cfg.jsrev;
+            var jsurl = M.cfg.wwwroot + '/lib/javascript.php?jsfile=/lib/flowplayer/flowplayer-3.2.8.min.js&rev=' + M.cfg.jsrev;
         }
         var fileref = document.createElement('script');
         fileref.setAttribute('type','text/javascript');
diff --git a/lib/javascript.php b/lib/javascript.php
index 8ec42631c86..380334f52ad 100644
--- a/lib/javascript.php
+++ b/lib/javascript.php
@@ -43,7 +43,7 @@ if ($slashargument = min_get_slash_argument()) {
 
 } else {
     $rev  = min_optional_param('rev', 0, 'INT');
-    $file = min_optional_param('file', '', 'RAW');
+    $file = min_optional_param('jsfile', '', 'RAW'); // 'file' would collide with URL rewriting!
 }
 
 // some security first - pick only files with .js extension in dirroot
diff --git a/lib/outputrequirementslib.php b/lib/outputrequirementslib.php
index e1d88322b97..2d32ec9db60 100644
--- a/lib/outputrequirementslib.php
+++ b/lib/outputrequirementslib.php
@@ -406,7 +406,7 @@ class page_requirements_manager {
             }
             if (!empty($CFG->cachejs) and !empty($CFG->jsrev) and $CFG->jsrev > 0 and strpos($url, '/lib/editor/') !== 0 and substr($url, -3) === '.js') {
                 if (empty($CFG->slasharguments)) {
-                    return new moodle_url($CFG->httpswwwroot.'/lib/javascript.php', array('rev'=>$CFG->jsrev, 'file'=>$url));
+                    return new moodle_url($CFG->httpswwwroot.'/lib/javascript.php', array('rev'=>$CFG->jsrev, 'jsfile'=>$url));
                 } else {
                     $returnurl = new moodle_url($CFG->httpswwwroot.'/lib/javascript.php');
                     $returnurl->set_slashargument('/'.$CFG->jsrev.$url);
diff --git a/theme/yui_combo.php b/theme/yui_combo.php
index 77fe9011816..bafcc1ef62f 100644
--- a/theme/yui_combo.php
+++ b/theme/yui_combo.php
@@ -209,12 +209,17 @@ function combo_not_found($message = '') {
 }
 
 function combo_params() {
-    // note: buggy or misconfigured IIS does return the query string in REQUEST_URL
-    if (isset($_SERVER['REQUEST_URI']) and strpos($_SERVER['REQUEST_URI'], '?') !== false) {
+    if (isset($_SERVER['QUERY_STRING']) and strpos($_SERVER['QUERY_STRING'], 'file=/') === 0) {
+        // url rewriting
+        $slashargument = substr($_SERVER['QUERY_STRING'], 6);
+        return array($slashargument, true);
+
+    } else if (isset($_SERVER['REQUEST_URI']) and strpos($_SERVER['REQUEST_URI'], '?') !== false) {
         $parts = explode('?', $_SERVER['REQUEST_URI'], 2);
         return array($parts[1], false);
 
     } else if (isset($_SERVER['QUERY_STRING']) and strpos($_SERVER['QUERY_STRING'], '?') !== false) {
+        // note: buggy or misconfigured IIS does return the query string in REQUEST_URI
         return array($_SERVER['QUERY_STRING'], false);
 
     } else if ($slashargument = min_get_slash_argument()) {