Prevent TypeError on <style> tags

include.js

@@ -199,7 +199,7 @@
 
         // loop on document stylesheets to check if media is loaded
         while (i--) {
-            if (sheets[i].href.indexOf(href) != -1) {
+            if (sheets[i].href && sheets[i].href.indexOf(href) != -1) {
                 elem.setAttribute('data-loaded', true);
                 self.onModuleLoaded(elem.getAttribute('data-module'), elem.getAttribute('data-count'));
                 return;

minify.json

@@ -0,0 +1,27 @@
+{
+    "compress": {
+        "sequences": true,
+        "properties": true,
+        "dead_code": true,
+        "drop_debugger": true,
+        "conditionals": true,
+        "comparisons": true,
+        "evaluate": true,
+        "booleans": true,
+        "loops": true,
+        "unused": true,
+        "hoist_funs": true,
+        "if_return": true,
+        "join_vars": true,
+        "cascade": true,
+        "warnings": true,
+        "negate_iife": true,
+        "unsafe": false,
+        "hoist_vars": false,
+        "pure_getters": false,
+        "drop_console": false,
+        "keep_fargs": false,
+        "toplevel": false
+    },
+    "mangle": {}
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "include.js",
-  "version": "3.0.3",
+  "version": "3.0.5",
   "description": "**Include.js** is a tiny Javascript loader. It can load normal javascript files but is more efficient with **web modules**.",
   "main": "include-min.js",
   "dependencies": {},
@@ -14,10 +14,12 @@
     "karma-jasmine": "^1.0.2",
     "karma-opera-launcher": "^1.0.0",
     "karma-phantomjs-launcher": "^1.0.2",
-    "karma-safari-launcher": "^1.0.0"
+    "karma-safari-launcher": "^1.0.0",
+    "uglify-es": "^3.1.2"
   },
   "scripts": {
-    "test": "karma start test/karma.conf.js --single-run"
+    "test": "karma start test/karma.conf.js --single-run",
+    "compress": "uglifyjs include.js --config-file minify.json -o include-min.js"
   },
   "repository": {
     "type": "git",