Grapesjs editor.gethtml() not work in Edge Explorer

In my project i'm using this code to get the html from the grapesjs editor:

var html = window.frames[0].editor.getHtml();

my editor is in iframe and is displayed in another page, and it works good in chrome and mozzila but in edge i cannot get the html code because i can see this javascript error:

Unable to get property 'getHtml' of undefined or null reference

It seems like cannot find the editor with the previous code? why? is there any suggestions?