CSS: Skip the px-appending logic for animations of non-element props

Without this change animating properties from jQuery.cssNumber on non-elements
throws an error.

Ref gh-4055
Closes gh-4061

1 files changed, 11 insertions, 0 deletions

diff --git a/test/unit/effects.js b/test/unit/effects.js
index 462524ef3..e297273e4 100644
--- a/test/unit/effects.js
+++ b/test/unit/effects.js
@@ -607,6 +607,17 @@ QUnit.test( "animate non-element", function( assert ) {
 	this.clock.tick( 200 );
 } );
 
+QUnit.test( "animate non-element's zIndex without appending \"px\"", function( assert ) {
+	assert.expect( 1 );
+
+	var obj = { zIndex: 0 };
+
+	jQuery( obj ).animate( { zIndex: 200 }, 200, function() {
+		assert.equal( obj.zIndex, 200, "The custom property should be modified without appending \"px\"." );
+	} );
+	this.clock.tick( 200 );
+} );
+
 QUnit.test( "stop()", function( assert ) {
 	assert.expect( 4 );