Gray out a check box based on a specific selection

[fpdan]

Hello all, I have a form that I have created that I need to gray out a specific checkbox based on whether or not another specific checkbox is selected or not.

Here's my checkbox code:

<input name="hullcolorcustom" type="checkbox" value="750" onclick="addUp()">
              Hull Color Custom...................................................$750<br>
              <input name="deckcolor" type="checkbox" value="1100" onclick="addUp()">
              Deck Color..............................................................$1,100<br>
              <input name="remtackle" type="checkbox" value="450" onclick="addUp()">
              Removable Tackle Center w/ 9 boxes.......................$450

Any ideas how I could disable the "hullcolorcustom" checkbox if "deckcolor" is selected? I think it needs to be done with an if statement but I have been unsuccessfull up to this point getting this to work.

[Kudose]

Something like this:

function addUp(){
  var deckColor = document.getElementsByName('deckcolor')[0];
  if(deckcolor.checked)
    document.getElementsByName('hullcustomcolor')[0].setAttribute('disabled', 'true');
}

That is javascript.