Some problems in IFRAME programming

A few days ago to do an IFRAME display diagram of the demo, found the contentdocument binding to the IFRAME

The onclick event is not valid, and the onclick of the iframe.contentdocument in the page

The property is undefined, and when the IFRAME is removed from the SRC attribute, the event takes effect when the OnClick event is bound to it;

Compared to the original when the Iframe.contentdocument binding event, the IFRAME has not yet loaded

Complete, the event handler can be bound for contentdocument, but it cannot be executed.

Because Contentdocument is empty at this point, you can observe that the URL of this page is About:blank

　　

        var f = document.createelement (' iframe ');         = '.. /promise/promise.html ';        Document.body.appendChild (f)        function() {console.log (123)}        Console.log ( F.contentdocument.onclick)    

and

        function () {            function() {console.log (123)}            console.log (F.contentdocument.onclick)        }    

Wait for the IFRAME to load and then bind the event to resolve the issue.

Some problems in IFRAME programming