Zip Component, Email Component, Encryption Component ActiveX Control for Zip Compression .NET Components for ASP.NET
ActiveX and .NET Components for Zip Compression, Encryption, Email, XML, S/MIME, HTML Email, Character Encoding, Digital Certificates, FTP, and more ASP Email ActiveX Component

Index of Chilkat Blog Posts

February 9, 2006


This is a very important bit of information to know:
.eml files are identical to .mht files. The only difference is the filename extension.

Both simply contain MIME text. You can save (almost) any web page from Internet Explorer as a .mht (web archive), rename it by giving it a .eml extension, and then double-click on it. You’ll notice that the default application for .eml is Outlook Express. It will display the HTML "email", but with no From, To, CC, or Subject. You may then add these and send the email.

With Chilkat, if you already have a .mht file, you may load it into an email object by calling Chilkat.Email.LoadEml (or Chilkat.Email.SetFromMimeText), then set the Subject & From properties, and then call AddTo/AddCC/AddBcc for each recipient, and send.

However, there is one important distinction: HTML emails really shouldn’t contain Javascript. Email clients flag Javascript as a security threat. Also, images that are not embedded may be a problem. When Internet Explorer creates the MHT, offsite images are not embedded. A typical trick of spammers is to use an image URL such that it identifies the recipient of the email. If the HTTP request for the image arrives at their web server (via the loading and displaying of the email in the email client, such as Outlook), then they know that the email was received and that the email address is good. Advance email clients, such as Mozilla’s Thunderbird, will automatically block the loading of these images. If you are sending an HTML email, perhaps a newsletter, then you want two things:

1) All images to be embedded.
2) No Javascript

The Chilkat MHT component takes care of #1 as best as possible — assuming the images can be downloaded and embedded in the email at the time of the function call. Chilkat MHT (in the calls that return EML) strips Javascript and selects the "noscript" option from within the HTML if it is present.

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