diff --git a/godoc/static/static.go b/godoc/static/static.go
index a024ca09..74338bf7 100644
--- a/godoc/static/static.go
+++ b/godoc/static/static.go
@@ -2860,6 +2860,12 @@ pre .selection-comment {
 pre .ln {
 	color: #999;
 }
+.ln {
+	-webkit-user-select: none;
+	-moz-user-select: none;
+	-ms-user-select: none;
+	user-select: none;
+}
 body {
 	color: #222;
 }
diff --git a/godoc/static/style.css b/godoc/static/style.css
index b21bc24f..958f0146 100644
--- a/godoc/static/style.css
+++ b/godoc/static/style.css
@@ -30,6 +30,12 @@ pre .selection-comment {
 pre .ln {
 	color: #999;
 }
+.ln {
+	-webkit-user-select: none;
+	-moz-user-select: none;
+	-ms-user-select: none;
+	user-select: none;
+}
 body {
 	color: #222;
 }