Coloring a boarder for a cell, java script problems

I am trying to color a border based on value entered into the cell within a form.

The cell is a numeric field

Below is the scripted for the cell.

Not sure why it is not working. I

form1.#subform[0].Table2.Row1.FFMCRow1::calculate - (JavaScript, client)

var v = Number(event.value);

if (v>=0 && v<=73) {event.target.borderColor = ["CMYK",1,0,0,0];}

else if (v>73 && v<=84) {event.target.borderColor = ["RGB",0,0.8,0];}

else if (v>84 && v<=88) {event.target.borderColor = color.yellow;}

else if (v>88 && v<=91) {event.target.borderColor = color.red;}

else if (v>=92) {event.target.borderColor = color.magenta;}

Any thoughts of suggestions would be appreciated.