Dynamic legend based on what's on the screen?

[MatthewKing]

Is there a way to make the legend only show the features that are on the screen?  Here's an application that I'm working on ArcGIS Web Application and when I zoom down to one of the sites and display the legend it displays the trails for all of the sites, not just the one on the screen.  Is that even possible?

Thanks!

Matt

[RobertScheitlin__GISP]

Matt,

  It may be possible with tons of programming.

[MatthewKing]

I was afraid that would be the answer.  I knew it was possible with ArcMap (and looking at that I realized I forgot the term "map extent" instead of "what's on the screen"  )