In CSS:
textarea {
border-style: none;
border-color: Transparent;
overflow: auto;
}
textarea {
border: 0;
overflow: auto; }
less CSS ^ you can't align the text to the bottom unfortunately.
This one is great:
<style type="text/css">
textarea.test
{
width: 100%;
height: 100%;
border-color: Transparent;
}
</style>
<textarea class="test"></textarea>
Source: Stackoverflow.com