On this article we focus on the exact HTML tags, attributes and parameters that are ignored by popular email clients, such as Outlook, Gmail or Outlook.com.
HTML tags ignored by Outlook
Outlook is using the Office / Word HTML rendering engine which does not support all HTML 4 tags / attributes. Here is a list of tags / attributes / parameters that are NOT supported by Outlook:
background (only when there is a URL)
media ( screen | print | projection | braille | speech | all )
cue-before, cue-after, cue
pause-before, pause-after, pause
HTML tags ignored by Gmail
Well, Outlook is not the only email client that doesn’t fully support HTML. In fact, all email clients have various HTML rendering limitations. Gmail simply ignores all code added to the HEAD email section, so you can’t define any page-wide CSS STYLE and you must use inline CSS on each line. It also pretty much ignores padding and margin declarations (margin, margin-top, margin-left, etc).
HTML tags ignored by Outlook.com
Outlook.com has absolutely no relation to Microsoft Office Outlook, when it comes to understanding & rendering HTML emails. Outlook.com ignores margin declarations (margin-left, margin-right, margin-top, margin-bottom) and it also ignores the “float” CSS style.
Are there any workarounds to the limited email HTML support?
When it comes to margins, the best solutions are to use the span padding attribute (instead of margin-top/left/right/bottom) or simply to add extra columns in your table, in order to space the desired objects.
If your email campaign targets only certain email clients, you can fix this issue by coding your email to load different code sections depending on each email client application. While it’s not a bullet proof solution, it can get your HTML email to display properly on most email clients.
However, if you want to keep your email as clean as possible, here are some quick advices on coding HTML emails:
– do not use external CSS files and do not define your CSS styles in the email HTML HEAD section. Use inline CSS;
– avoid using background images, as they usually get ignored;
– avoid designing critical parts of your HTML email as images. Since images are heavily used by many email campaign providers to generate various email delivery reports, most modern email clients choose to ignore images by default;
– do not design your HTML email using DIVs. Instead, create your layout using tables;
– do not use videos or Flash files inside your HTML email. They get ignored by most email clients;
– use clean, W3C validated HTML code.
Read more: how to insert clean HTML code to Outlook emails.