I often forget the differences between a form element that is disabled to a form element that is readonly.
From the interface perspective, both usually achieve what I desire - prohibiting the end user from changing a value that is calculated or pre-set, but is necessary to have on the form.
I have extracted these differences from the Definition by W3C.
|Disabled Controls||Read-only Controls|
|Definition||When set for a form control, this boolean attribute disables the control for user input.||When set for a form control, this boolean attribute prohibits changes to the control.|
|Effects on an element||
BUTTON, INPUT, OPTGROUP, OPTION, SELECT, and TEXTAREA
|INPUT and TEXTAREA|