How can I add <!DOCTYPE html> inside an iframe in GWT?

I've created an IFrame with no src in my GWT project but as I don't have <!DOCTYPE html> inside it some css properties are being overriden by the user agent stylesheet. Is there any way I can add <!DOCTYPE html> inside the IFrame element?

Solution

I guess that you want to have an empty iframe to manipulate programmatically.

The easiest way is to create minimal html file with <!DOCTYPE html> and set src attribute to that file.

<!DOCTYPE html>
<html>
    <head>
        <title>Title</title>
    </head>
    <body>
    </body>
</html>

Save this file is the war folder as empty.html for example. Then use:

IFrameElement iframe = Document.get().createIFrameElement();
iframe.setSrc("empty.html");

to get Element. If you want to have a Widget add:

new HTML(iframe.toString());