Usually small devices have limited memory and CPU power. Execution of script programs may not be supported. Contents should be readable even if scripts are not executed. Also, just as in the case for style sheets, scripts can be included by reference. Event handler attributes used to invoke script programs are not supported.
Events are device dependent.
An incoming-call event is unlikely to happen in a television. A generic event handling mehanism would be more appropriate than hardwiring the event names in the document type definition. Many simple Web clients cannot display text that is more complex than mono-space. Bi-directional text, bold faced font, and other text extension elements are not supported. It is recommended that style sheets are used to create a presentation that is appropriate for the device.