WordPress/wp-admin/js/set-post-thumbnail.min.js

function WPSetAsThumbnail(a,b){var c=jQuery("a#wp-post-thumbnail-"+a);c.text(setPostThumbnailL10n.saving),jQuery.post(ajaxurl,{action:"set-post-thumbnail",post_id:post_id,thumbnail_id:a,_ajax_nonce:b,cookie:encodeURIComponent(document.cookie)},function(b){var d=window.dialogArguments||opener||parent||top;c.text(setPostThumbnailL10n.setThumbnail),"0"==b?alert(setPostThumbnailL10n.error):(jQuery("a.wp-post-thumbnail").show(),c.text(setPostThumbnailL10n.done),c.fadeOut(2e3),d.WPSetThumbnailID(a),d.WPSetThumbnailHTML(b))})}