<form>
<input type=text onkeypress="this.form.cmd.style.display='block'">
<input type=submit name=cmd style="display:none">
</form>
<input type=text onkeypress="this.form.cmd.style.display='block'">
<input type=submit name=cmd style="display:none">
</form>
<input type=text onkeypress="this.form.cmd.disabled=false">
<input type=submit name=cmd disabled>
</form>