Q:

What are the Device Filters?

I always get this Error when I mistype a tag in an aspx file:
"Unrecognized tag prefix or device filter"
I know what tag prefix is , but I don't have good information about Device Filters. 
Can any one help me find a comprehensive resource to learn about this topic because I looked it up on the internet and I found the Microsoft website which had only excerpts and no examples.

A:

See this:
"Using device filters, applications can customize the appearance of controls for specific hardware devices or for categories of devices. The customization is based on the capabilities of the hardware device being used to browse the application...."
http://msdn.microsoft.com/en-us/library/4a28z6x5(v=vs.80).aspx
http://msdn.microsoft.com/en-us/library/0ffa7b0h(v=vs.71).aspx

