starting to annotate JavaScript APIs in the standard library

libraries/stdlib/src/js/Annotations.kt

@@ -0,0 +1,13 @@
+package js
+
+/**
+ * This annotation marks code as being a native JavaScript expression
+ */
+native
+annotation class native(name : String = "") {}
+
+/**
+ * Represents a function in the standard library
+ */
+native
+annotation class library(name : String = "") {}

libraries/stdlib/src/kotlin/browser/Properties.kt

@@ -1,13 +1,14 @@
 package kotlin.browser
 
 import org.w3c.dom.Document
+import js.native
 
 private var _document: Document? = null
 
 /**
  * Provides access to the current active browsers DOM for the currently visible page.
  */
-var document: Document
+native var document: Document
  get() = _document!!
  set(value) {
      _document = value