[popup] On WP7, you get "" for an empty background, not undefined, like in IE8

Gabriel Schulhof · Gabriel Schulhof · commit 5463fc84dcad · 2012-08-15T13:27:43.000+03:00
diff --git a/js/widgets/popup.js b/js/widgets/popup.js
@@ -220,7 +220,8 @@ define( [ "jquery",
 					"ui-popup-screen-background-hack",
 					( this._ui.screen.css( "background-color" ) === "transparent" &&
 						this._ui.screen.css( "background-image" ) === "none" &&
-						this._ui.screen.css( "background" ) === undefined ) );
+						( this._ui.screen.css( "background" ) === undefined ||
+							this._ui.screen.css( "background" ) === "" ) ) );
 			}
 
 			if ( this._isOpen ) {

Original file line number	Diff line number	Diff line change
`@@ -220,7 +220,8 @@ define( [ "jquery",`
`220`	`220`	`"ui-popup-screen-background-hack",`
`221`	`221`	`( this._ui.screen.css( "background-color" ) === "transparent" &&`
`222`	`222`	`this._ui.screen.css( "background-image" ) === "none" &&`
`223`		`- this._ui.screen.css( "background" ) === undefined ) );`
	`223`	`+ ( this._ui.screen.css( "background" ) === undefined \|\|`
	`224`	`+ this._ui.screen.css( "background" ) === "" ) ) );`
`224`	`225`	`}`
`225`	`226`
`226`	`227`	`if ( this._isOpen ) {`