? css expression question

Hello:

Using IE 6, I have several ' disabled="disabled")
readonly (html--> readonly="readonly")

If an input tag is either readonly OR disabled, I need to gray out the background color.

I thought that this might work, but it does not:
------------------
input{
background-color:expression((this.disabled==true)?'#E3E3E3':'');
background-color:expression((this.readOnly==true)?'#E3E3E3':'');
}
------------------

However, if I use just one of these at a time, that expression is evaluated and works. Perhaps I need a more advanced expression that can check either state in one shot.

But I don't know how that's done. :shrug:
ANY ADVICE ?
thnx!