window.document.onkeydown = disableRefresh;

function disableRefresh(evt){

evt = (evt) ? evt : window.event

if (evt.keyCode) {

   if(evt.keyCode == 116){

     //do something

   }

}

}

keycode 8 = BackSpace BackSpace

keycode 9 = Tab Tab

keycode 12 = Clear

keycode 13 = Enter

keycode 16 = Shift_L

keycode 17 = Control_L

keycode 18 = Alt_L

keycode 19 = Pause

keycode 20 = Caps_Lock

keycode 27 = Escape Escape

keycode 32 = space space

keycode 33 = Prior

keycode 34 = Next

keycode 35 = End

keycode 36 = Home

keycode 37 = Left

keycode 38 = Up

keycode 39 = Right

keycode 40 = Down

keycode 41 = Select

keycode 42 = Print

keycode 43 = Execute

keycode 45 = Insert

keycode 46 = Delete

keycode 47 = Help

keycode 48 = 0 equal braceright

keycode 49 = 1 exclam onesuperior

keycode 50 = 2 quotedbl twosuperior

keycode 51 = 3 section threesuperior

keycode 52 = 4 dollar

keycode 53 = 5 percent

keycode 54 = 6 ampersand

keycode 55 = 7 slash braceleft

keycode 56 = 8 parenleft bracketleft

keycode 57 = 9 parenright bracketright

keycode 65 = a A

keycode 66 = b B

keycode 67 = c C

keycode 68 = d D

keycode 69 = e E EuroSign

keycode 70 = f F

keycode 71 = g G

keycode 72 = h H

keycode 73 = i I

keycode 74 = j J

keycode 75 = k K

keycode 76 = l L

keycode 77 = m M mu

keycode 78 = n N

keycode 79 = o O

keycode 80 = p P

keycode 81 = q Q at

keycode 82 = r R

keycode 83 = s S

keycode 84 = t T

keycode 85 = u U

keycode 86 = v