Checkbox Que Atualiza Valor Total

Galera to tentando criar um sistema de pedidos online e tenho esse codigo aqui já pronto

<td colspan="3"><h4><center>Adicionais</center></h4></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="2" onClick="soma(this)"> L. Ninho</td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="3" onClick="soma(this)"> Nutella<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="3" onClick="soma(this)"> Chantilly<br></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.5" onClick="soma(this)"> L. Condensado<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.5" onClick="soma(this)"> S. Valsa<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="2.5" onClick="soma(this)"> Sorvete<br></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="2.5" onClick="soma(this)"> Chocolate<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="2" onClick="soma(this)"> Kit Kat<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="2" onClick="soma(this)"> Confete<br></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Morango<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Banana<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Granola<br></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Kiwi<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Manga<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Pessego<br></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="2.00" onClick="soma(this)"> Ovomaltine<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.00" onClick="soma(this)"> Mel<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.00" onClick="soma(this)"> Paçoca<br></td>
 </tr>
 <tr>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> C. Caramelo<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Bis<br></td>
 <td><input type="checkbox" autocomplete="off" name="valor" value="1.50" onClick="soma(this)"> Chocoball<br></td>
 </tr>

<script type="text/javascript">
(function() {
 var elements = document.getElementsByTagName('input');
 var resultado = document.getElementById('resultado_soma');
 var total = 100.00;

 for (var i = 0; i < elements.length; i++) {
 elements[i].onclick = function() {
 if (this.checked === false) {
 total = total - this.value;
 } else {
 total = total + parseFloat(this.value);
 }

 resultado.innerHTML = total;
 }
 }
})();
</script>

eu quero que ele exiba o valor aqui

<h4 class="classic-title"><span>Valor Total:</span></h4>
 <h1> <?php echo $lndet['valorin'] + $valor ?>R$ </h1>

coisa que não está acontecendo... alguem me ajuda