diff --git a/README.md b/README.md
index a16c9ad..c037995 100644
--- a/README.md
+++ b/README.md
@@ -61,12 +61,13 @@ $( '.uls-trigger' ).uls( {
 
 | Option      | Description |
 |-------------|---------------------|
-| left        | Left position of ULS dialog. E.g: 100px or 20% |
-| top         | Top position of ULS dialog. E.g: 100px or 20% |
+| left        | DEPRECATED: use onPosition |
+| top         | DEPRECATED: use onPosition |
 | onSelect    | Callback function when user selects a language. |
 | onCancel    | Callback function when the dialog is closed without selecting a language. |
 | onReady     | Callback function when ULS has initialized. |
 | onVisible   | Callback function when ULS dialog is shown. |
+| onPosition  | Callback for positioning the dialog. It should return an object with any of the keys `top`, `right`, `bottom` and `left`. |
 | languages   | List of selectable languages. Defaults to all known languages. |
 | menuWidth   | Override the automatic choice of menu width. One of narrow, medium, wide (1, 2, 4 columns respectively). |
 | ulsPurpose  | A string that will identify this instance of ULS. It's useful if you have several instances of ULS in your web application and you want to have a unique identifier for each of them. |
diff --git a/src/jquery.uls.core.js b/src/jquery.uls.core.js
index 8661578..fcf489d 100644
--- a/src/jquery.uls.core.js
+++ b/src/jquery.uls.core.js
@@ -119,6 +119,11 @@
 				top = this.top,
 				left = this.left;
 
+			if ( this.options.onPosition ) {
+				return this.options.onPosition.call( this );
+			}
+
+			// Default implementation (middle of the screen under the trigger)
 			if ( top === undefined ) {
 				pos = $.extend( {}, this.$element.offset(), {
 					height: this.$element[ 0 ].offsetHeight
@@ -380,9 +385,9 @@
 	};
 
 	$.fn.uls.defaults = {
-		// CSS top position for the dialog
+		// DEPRECATED: CSS top position for the dialog
 		top: undefined,
-		// CSS left position for the dialog
+		// DEPRECATED: CSS left position for the dialog
 		left: undefined,
 		// Callback function when user selects a language
 		onSelect: undefined,
@@ -392,6 +397,8 @@
 		onReady: undefined,
 		// Callback function when ULS dialog is shown
 		onVisible: undefined,
+		// Callback function when ULS dialog is ready to be shown
+		onPosition: undefined,
 		// Languages to be used for ULS, default is all languages
 		languages: $.uls.data.getAutonyms(),
 		// The options are wide (4 columns), medium (2 columns), and narrow (1 column).