how to use --disable-web-security??

can't runjs to frame document.
Uncaught DOMException: Failed to read a named property 'document' from 'Window': Blocked a frame with origin "https://**.com" from accessing a cross-origin frame.
at <anonymous>:2:64
???? @ VM1604:2

var iframe = document.querySelector("#pt_iframe");
error here:
var iframeDoc = iframe.contentDocument || iframe.contentWindow.document;