Fix #10978: Let jQuery.param() accept non-native constructed objects.

src/ajax.js

@@ -814,11 +814,11 @@ function buildParams( prefix, obj, traditional, add ) {
 				// a server error. Possible fixes are to modify rack's
 				// deserialization algorithm or to provide an option or flag
 				// to force array serialization to be shallow.
-				buildParams( prefix + "[" + ( typeof v === "object" || jQuery.isArray(v) ? i : "" ) + "]", v, traditional, add );
+				buildParams( prefix + "[" + ( typeof v === "object" ? i : "" ) + "]", v, traditional, add );
 			}
 		});
 
-	} else if ( !traditional && jQuery.isPlainObject( obj ) ) {
+	} else if ( !traditional && jQuery.type( obj ) === "object" ) {
 		// Serialize object item.
 		for ( var name in obj ) {
 			buildParams( prefix + "[" + name + "]", obj[ name ], traditional, add );

test/unit/ajax.js

@@ -1032,16 +1032,24 @@ test("jQuery.param()", function() {
 });
 
 test("jQuery.param() Constructed prop values", function() {
-	expect(3);
+	expect( 4 );
 
-	var params = {"test": new String("foo") };
+	function Record() {
+		this.prop = "val";
+	}
+
+	var params = { "test": new String("foo") };
 	equal( jQuery.param( params, false ), "test=foo", "Do not mistake new String() for a plain object" );
 
-	params = {"test": new Number(5) };
+	params = { "test": new Number(5) };
 	equal( jQuery.param( params, false ), "test=5", "Do not mistake new Number() for a plain object" );
 
-	params = {"test": new Date() };
+	params = { "test": new Date() };
 	ok( jQuery.param( params, false ), "(Non empty string returned) Do not mistake new Date() for a plain object" );
+
+	// should allow non-native constructed objects
+	params = { "test": new Record() };
+	equal( jQuery.param( params, false ), jQuery.param({ "test": { prop: "val" } }), "Allow non-native constructed objects" );
 });
 
 test("synchronous request", function() {