readonly checkbox

 We can use javascript to make a checkbox read only(not disabled) as shown below

<input type="checkbox" checked onkeydown="return false;" onclick="return false;" />

if you want to disable check using keyboard modify above as follows.

<input type="checkbox" checked onclick="return false;" onkeydown="e = e || window.event; if(e.keyCode !== 9) return false;"/>

Cheer

Samitha