disable input without hiding it

is there a way to disable a input without hiding it?

You can use disableItem() method:

form.disableItem(“ID”);

That doesnt work, cant find method or funtion for this object.

already have it working with this:
viewtopic.php?f=17&t=15018&p=47298&hilit=set+type#p47298

but where can i change the css so the input looks darker when its disabled?

fyi the correct method name is

_disableItem()