Quale in particolare?
<div id="contactform">
<form id="contact" action="#">
<fieldset>
<span class="error" id="name_error">Per favore inserisci il tuo nome !</span>
<span class="error" id="email_error">Per favore inserisci la tua e-mail!</span>
<span class="error" id="email_error2">Per favore inserisci la tua e-mail!</span>
<span class="error" id="msg_error">Per favore inserisci il tuo messaggio !</span>
<input type="text" name="Name" id="name" size="50" value="Name" class="text-input" onBlur="if (this.value == ''){this.value = 'Name'; }" onFocus="if (this.value == 'Name') {this.value = ''; }" />
<input type="text" name="email" id="email" size="50" value="Email" class="text-input" onBlur="if (this.value == ''){this.value = 'Email'; }" onFocus="if (this.value == 'Email') {this.value = ''; }" />
<input type="text" name="subject" id="subject" value="Subject" class="text-input" onBlur="if (this.value == ''){this.value = 'Subject'; }" onFocus="if (this.value == 'Subject') {this.value = ''; }" />
<textarea cols="60" rows="10" name="msg" id="msg" class="text-input">Message</textarea>
<br />
<input type="submit" name="submit" class="button" id="submit_btn" value="Invia Messaggio"/><br class="clear" />
</fieldset>
</form>
</div><!-- end contactform -->