I have faced the mail content design problems from starting carrier...
But every time I am used to @ClientType() and manipulate the data depends on notes or web.
And I struggled with HTML content of mail for other mail domains.
I suffered a lot with 8.5.1...
I used NotesRichTextItem ParseHTML...
But Everything had failed in one situation...
use of NotesMIMEEntity class is working fine... But it needs to be declared each and every time,
I got a solution from Mark Leusink blog.,
He is telling nice solution for that.,
Do the following,
Step 1: Add the download file and put this code into your script library as "xpHTMLMail", Script code
Step 2: Add the following code into your button click.,
var mail = new HTMLMail();
mail.setTo( "email@example.com" );
mail.setSubject( "Have a nice day!" );
mail.addHTML( "<b style=\"color:red\">Hai Have a Nice Day... <b>" );
For more info, click