Form: Rename from `.form()` to `._form()` since its not for public use

Fixes #15074
Closes gh-1760

3 files changed, 3 insertions, 3 deletions

diff --git a/ui/form-reset-mixin.js b/ui/form-reset-mixin.js
index a14c82ee6..5d182186a 100644
--- a/ui/form-reset-mixin.js
+++ b/ui/form-reset-mixin.js
@@ -42,7 +42,7 @@ return $.ui.formResetMixin = {
 	},
 
 	_bindFormResetHandler: function() {
-		this.form = this.element.form();
+		this.form = this.element._form();
 		if ( !this.form.length ) {
 			return;
 		}
diff --git a/ui/form.js b/ui/form.js
index cfb4bd280..fb0a3c6cf 100644
--- a/ui/form.js
+++ b/ui/form.js
@@ -13,7 +13,7 @@
 // Support: IE8 Only
 // IE8 does not support the form attribute and when it is supplied. It overwrites the form prop
 // with a string, so we need to find the proper form.
-return $.fn.form = function() {
+return $.fn._form = function() {
 	return typeof this[ 0 ].form === "string" ? this.closest( "form" ) : $( this[ 0 ].form );
 };
 
diff --git a/ui/widgets/checkboxradio.js b/ui/widgets/checkboxradio.js
index 19ae92811..228c9fab9 100644
--- a/ui/widgets/checkboxradio.js
+++ b/ui/widgets/checkboxradio.js
@@ -161,7 +161,7 @@ $.widget( "ui.checkboxradio", [ $.ui.formResetMixin, {
 
 			// Not inside a form, check all inputs that also are not inside a form
 			group = $( nameSelector ).filter( function() {
-				return $( this ).form().length === 0;
+				return $( this )._form().length === 0;
 			} );
 		}