Introduction
Open Email Standards restrict outdated and obsolete HTML tags that pose security risks and are no longer supported by current email clients or browsers. Many of these tags were once used for layout and interactivity, but have since been replaced by modern, safer alternatives. Avoiding them not only ensures a more secure and consistent experience across devices, but also helps create future-proof emails that render reliably without introducing unnecessary vulnerabilities.
Tags to Avoid
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<acronym>, <big>, <strike>, <tt>: Presentational tags replaced by CSS and modern semantic elements. -
<basefont>, <font>: Obsolete font styling elements that conflict with modern styling practices. -
<center>: Deprecated alignment tag replaced by CSS. -
<frame>, <frameset>, <noframes>: Outdated layout structures incompatible with secure email rendering. -
<dir>: Replaced by<ul>for lists; no longer supported. -
<applet>: Used for Java applets; deprecated due to significant security risks. -
<bgsound>: IE-specific background audio tag; unsupported and invasive. -
<isindex>: Obsolete search input method replaced by standard form controls. -
<menuitem>: Deprecated tag related to<menu>not supported in modern environments. -
<marquee>: Legacy scrolling text tag, deprecated and unreliable.
Rationale for Exclusion
These tags were once used for layout and interactivity but have been replaced by modern alternatives. Their use in email is unnecessary and may introduce security issues or fail to render properly.