+// TODO 構文のサポート instanceof, in, try catch\r
+\r
+if( X_UA[ 'IE' ] < 7 ){ // error @ NN7.2\r
+ X_UA[ 'IE4' ] || X_UA[ 'IE5' ] || X_UA[ 'MacIE' ] ?\r
+ document.execCommand && document.execCommand( 'BackgroundImageCache', false, true ) :\r
+ (\r
+ X_Script_try( function(){ document.execCommand( 'BackgroundImageCache', false, true ); return 1; } ) &&\r
+ /**\r
+ * ie7 以下で実行する document.execCommand( 'BackgroundImageCache', false, true ) の失敗。\r
+ * bonus: hotfix for IE6 SP1 (bug KB823727)\r
+ * multipleIEs IE6 standalone 版では不可, IE5.5 は可,,,\r
+ * @alias X.UA.ieExeComError */ \r
+ ( X_UA[ 'ieExeComError' ] = true )\r
+ //eval( 'var a=1;try{document.execCommand&&document.execCommand("BackgroundImageCache",!1,!0)}catch(e){a=0}!a' )\r
+ );\r
+};\r