diff --git a/docs/reference/modules/scripting/advanced-scripting.asciidoc b/docs/reference/modules/scripting/advanced-scripting.asciidoc
index b4053d76598..a5fcc12777d 100644
--- a/docs/reference/modules/scripting/advanced-scripting.asciidoc
+++ b/docs/reference/modules/scripting/advanced-scripting.asciidoc
@@ -10,6 +10,8 @@ script inside a <<query-dsl-function-score-query,function score query>>.
 Statistics over the document collection are computed *per shard*, not per
 index.
 
+It should be noted that the `_index` variable is not supported in the painless language, but `_index` is defined when using the groovy language.
+
 [float]
 === Nomenclature: