disable a textfield

[guran]

If your script program sends a value to a text field (on a buttonclick for an example) it's still possible for the user to enter different things on the same field so to speak " from the outside" How do one make a textfield disabled from anything else than the program itself ?

[Algorithm]

<input type="text" disabled="disabled" readonly="readonly" />

Neither of these attributes are well-supported in older browsers, but they should do the trick.