<html> <body> <script> var iframe = document.createElement('iframe'); iframe.setAttribute("mozbrowser", "true"); iframe.addEventListener('mozbrowsershowmodalprompt', function(e) { if (e.detail.message == 'child:ready') { setTimeout(function() { iframe.setVisible(false); iframe.setVisible(true); setTimeout(function() { alert('parent:finish'); }, 0); }, 0); } }); document.body.appendChild(iframe); iframe.src = 'file_browserElement_SetVisibleFrames_Inner.html?child'; </script> </body> </html>