Questions about creating a JavaScript MGRS grid

I basically need a reality check on several points. For my browser-based map application, I need an MGRS grid. There is an existing question about MGRS grid overlays with OpenLayers, which is exactly what I want, but there wasn't really a satisfactory answer, so I am trying again but with some additional points. I am willi开发者_如何转开发ng to create the points that might used to draw line strings on the server-side, pass them to the GUI, then extend OpenLayers' Graticule to use those points. With that in mind, here are my questions:

1. Is there an existing Java library for calculating MGRS grid points?
2. Is there (despite finding no such thing so far) an existing JavaScript solution for creating an MGRS grid? Ultimately I need to show 1K/1K squares. It seems that I can fake it at the 100,000 meter square level with OpenLayers' existing graticule (Setting the intervals to six degrees), but as I zoom in, and trying to set the intervals to mimic 1k/1k squares, the grid does not look accurate.
3. Instead of drawing line strings, it would be nice if the grid was made up of actual square objects that could be referenced and, say, highlighted or assigned a background image to display the designator. That's where I really need a reality check. What would the performance be like in a browser-based application? I ask this because some co-workers have expressed skepticism about this idea performance-wise.