Ext.onReady(function(){
    if(Ext.get('btn-appt')){
         Ext.get('btn-appt').first().replaceWith({tag: 'a',  href: 'https://www.demandforced3.com/www/etile_scheduler_popup.jsp?d3cp_exid=strobeldentistry&d3cp_source=My%20Website', target: '_blank', html: '_' });
   }
});