Default text

<form method= "post" action = "mailto:frah@inf.rl.ac.uk">
<input type = "text" name = "Mytext" value = "Starting text" />
</form>

Maximum length

<form method= "post" action = "mailto:frah@inf.rl.ac.uk">
<input type = "text" name = "Mytext" maxlength = "4" />
</form>

Size

<form method= "post" action = "mailto:frah@inf.rl.ac.uk">
<input type = "text" name = "Mytext" size = "36" /><br />
<input type = "text" name = "Mytext2" size = "48" />
</form>