There are two ways to achieve the read-only effect of input: disabled and readonly.
Naturally, the effects of both are only read but not editable, but the two are very different.
Disabled indicates that the input is invalid and its value will not be passed to any program, such as asp, php, etc.
Readonly is simply unable to edit and does not affect the passing of its value.
Disabled use: <INPUT type=text name=username value=james disabled>
Readonly uses: <INPUT type=text name=partNumber value=1500 readonly>