Given the html
input {
color: blue
}
input:read-only {
color: red
}
input:-moz-read-only {
color: red
}
<input type="text" value="normal">
<input type="button" value="normal">
<input type="text" readonly="true" value="readonly">
<input type="button" readonly value="readonly">
Firefox (77 and 78 i have tested) shows the elements as:
blue, red, red, red (not-readonly, readonly, readonly, readonly)
Chrome and edgium show:
blue, blue, red, blue (not, not, readonly, not).
Mozilla (https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/readonly) say
Note: Only text controls can be made read-only, since for other controls (such as checkboxes and buttons) there is no useful distinction between being read-only and being disabled, so the readonly attribute does not apply.
Yet, firefox clearly interprets all inputs with a type of button as being readonly (at least for the CSS).
Is this correct? Chrome acts as I would have expected firefox to based on the mozilla page - the readonly attribute, even if applied, is ignored.
I am having a css issue which I dare say I can fix by specifying types in the CSS, but I am not sure if this is a firefox bug, or quirk.