How can I make a checkbox readonly? not disabled?

There is no property to make the checkbox readonly. But you can try this trick.

<input type="checkbox" onclick="return false" />

DEMO

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

http://jsfiddle.net/2srjc/

If you are worried about tab order, only return false for the keydown event when the tab key was not pressed:

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

http://jsfiddle.net/2srjc/149/

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