<form name="contactform" method="post" action="engine.php" id="ContactForm">
    <div>
        <div  class="wrapper">
        <label for="nome" style="float:left;" class="color3">*Nome:</label><a name="nome"></a>
            <div class="bg" style="border:thick #CCC"><input tabindex="1" name="nome" type="text" id="nome"  value="" placeholder="Scrivi qui il tuo nome" class="input" required/>
            </div>
        </div>
        <div  class="wrapper">
        <label for="oggetto" style="float:left;" class="color3">*Oggetto:</label><a name="oggetto"></a>
            <div class="bg" style="border:thick #CCC"><input tabindex="2" name="oggetto" type="oggetto" id="oggetto"  value="" placeholder="Oggetto della richiesta" class="input" required/>                                       </div>
        </div>
        <div  class="wrapper">
        <label for="email" style="float:left;" class="color3">*Email:</label><a name="email"></a>
            <div class="bg" style="border:thick #CCC"><input tabindex="3" name="email" type="email" id="email"  value="" placeholder="Digita la tua Email" class="input" required/>
            </div>
        </div>
        <div  class="textarea_box">
        <label for="messaggio" style="float:left;" class="color3">*Messaggio:</label>
            <div class="bg" style="border:thick #CCC"><textarea tabindex="4" name="messaggio" id="messaggio" placeholder="La tua richiesta" cols="50" rows="10"></textarea>
            </div>
            <input type="text" id="fred" name="fred" style="visibility: hidden;"/>
        </div>
<p style="color:#F00">*Tutti i campi sono obbligatori.</p>
<a><input class="button1" id="bottone" type="button" value="Invio" style="behavior: url(PIE.htc); cursor:pointer;"/></a>
<a href="#" class="button1" onClick="document.getElementById('ContactForm').reset()">Cancella</a>
    </div>
</form>