CSS: Inputs as same height

gistfile1

span, input {
    margin: 0;
    padding: 0;
}
span {
    display: inline-block;
    border: 1px solid black;
    height: 25px;
    overflow: hidden;
}
input {
    border: none;
    height: 100%;
}
input[type="submit"] {
    border-left: 1px solid black;
}​

<span><input type="text" /><input type="submit" /></span>​