You can call 'showMask' method to display a centered message before loading the panel content, and then call 'hideMask' method to hide it after loaded the panel content successfully. These two methods are extended from
http://www.jeasyui.com/forum/index.php?topic=3641.0$('#tt').tabs('add',{
id: 'rectab-',
border:false,
title: 'rectab-',
href: url,
loadingMessage: '',
closable:true,
onBeforeLoad: function(){
$(this).panel('showMask','<div class="panel-loading">Daten werden vom Server geladen.</div>')
},
onLoad: function(){
$(this).panel('hideMask')
}
});