Conversion: Suggestions and specifications for writing HTML emails

ArticleDirectory

• Image shielding rules
• Outlook 2007 restrictions

Http://www.ncxd.com/blog/article/1.html

 

 

As work requires, we need to prepare several HTML-format email pages. Because of the differences in source code filtering by various email service websites, we need to make the pages as compatible as possible.

I found two articles through the Great Baidu:

• How to compile HTML emails compatible with mainstream mailboxes by rice 2008.4.28
• Email Page code writing suggestions and specifications 2008.4.30

Here are the highlights:

For plain text Emails:

1. The mail title should not exceed 18 characters;
2. Each line must contain up to 34 characters.

For HTML emails:

1. the email title cannot exceed 18 characters.
2. HTML Code and images should not exceed 50kb.
3. we recommend that you set the page width to PX. The maximum page width is PX.
4. avoid using edge and non-mainstream HTML technologies.
5. tags such as body and meta can be ignored because they are filtered out in many email systems.
6. do not use CSS for layout. tables should be used for layout.
7. do not use external style sheets, do not write

Finally, Sohu's mailbox is weird. A space will be added after each text segment, leading to a line break that won't fit in the original normal layout, leading to layout disorder. Therefore, if you want to be compatible with Sohu mailboxes, you must be extremely careful about some compact la S and minimize the number of text segments to keep the width.
 

Image shielding rules

Blocking issue	AOL v. 6.0-9.0	Gmail	Hotmail	Yahoo!	Outlook 2000/XP	Microsoft Outlook 2003	Outlook Express w/sp2	Outlook Express w/o SP2
Whether or not images with external links are blocked by default	Yes	Yes	No	No	No	Yes	Yes	No
Can users set whether to block images?	Yes	No	Yes	Yes	Yes	Yes	Yes	Yes
Can users click a button to display the image in the email?	Yes	Yes	Yes	No	No	Yes	Yes	N/
Whether the image is displayed by default when the sender is in the user contact list	Yes	No	Yes	No	Yes	Yes	Yes	Yes
Can the sender display pictures by default in the ISP whitelist (this concept does not seem to exist in China)	Yes	N/	Yes	No	N/	N/	N/	N/
Whether the alt attribute is displayed when the image is blocked	No	Yes	No	No	No	No	No	N/
Display Windows theme style during Preview	No	No	No	No	Yes	Yes	Yes	Yes

Foxmail, commonly used by domestic users, does not seem to be able to block images in emails. I cannot find the relevant settings.

Once an image is blocked, the entire email will become invisible. Here are some suggestions:

1. Avoid using images, such as titles and links, for important content;
2. Create a Web page with the same content as the email, and then write a sentence at the top of the mail, similar to: "If you cannot view the mail content, click here to view it ";
3. The ALT attribute must be added to all images;
4. Height and width must be defined for all images;
5. Notify the recipient to add your sending Address to the White List.

Outlook 2007 restrictions

Because Outlook 2007 uses the word rendering engine to display mail content, many HTML attributes cannot be supported, such:
 

1. Background Image (this is important !)
2. CSS floating and positioning (this is useless)
3. Custom list item image (this is useless)
4. Flash (not available anyway)
5. GIF Animation
6. ALT attribute of the image (worth noting)
7. Form (not available anyway)
    

The above information is summarized in the First Half. With the development of the Internet, the correctness of the above information may change, but at present, it is enough to pay attention to this.

for example, I wrote an HTML email for an external remote CSS file. The email address sent to 126 and Tom. 126 filtered out CSS. Tom does not. However, when receiving the 126 email via Foxmail, the external style sheet was available again