I want a to completely fill an absolutely-sized parent container, with padding in the textarea. I have this working for Chrome using the follow
If the only problem your facing is the padding will be added to the 100% width and height, you may consider the box-sizing CSS3 property. here is an example
.box {
box-sizing: border-box;
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
width: 100px;
padding: 10px;
}
In this case the box will have a total width of 100px instead of 120px.
More about this property values check this link