用ajax更改变量

Question

I have a select box with product models

<select name="name" id="name">
<option value=" ">Seleccione cantidad</option>
<?php  
    $eliminar = $product['model'];
    $terms = substr($eliminar, 0, 9);
    $modelo_query = $this->db->query("SELECT * FROM product WHERE model LIKE '%" . $terms . "%'");
    $modelos = array();
    if ($modelo_query->num_rows > 0) {
        foreach ($modelo_query->rows as $result) {
            $modelos[] = array('modelo'      => $result['model'],);
?>
<option value="<?php echo $result['model']; ?>"><?php echo $result['model']; ?></option>
<?php } } ?>
</select>

When I select a option i need to change this $product['product_id']:

onclick="addQtyToCart('<?php echo $product['product_id']; ?>');"

and this:

id="quantity-<?php echo $product['product_id']; ?>" 

in this code:

<input type="text" name="quantity" value="" class="input-mini" id="quantity-<?php echo $product['product_id']; ?>"/>

<input type="button" value="<?php echo $button_cart; ?>" onclick="addQtyToCart('<?php echo $product['product_id']; ?>');" class="btn btn-cart btn-small" />

The function addQtyToCart:

<script type="text/javascript">
        function addQtyToCart(product_id) {
          var qty = document.getElementById("quantity-" + product_id).value;
          addToCart(product_id, qty);
          document.getElementById("quantity-" + product_id).value = "";
        }
    </script>

Answer 1

In this part, you are using JavaScript instead of AJAX.

You could add the onchange attribute to your <option> element to execute a Javascript function when the selected option changes. Then, you could create a new javascript function that changes the ID and OnClick attributes that does the following:

function changeAttributes() {
var myID = document.getElementById('nameOfYourID');
myID.setAttribute('onclick','nameOfYourFunctionToCall');
myID.setAttribute('id', 'newNameOfYourID'); //sets the attribute id to newNameOfYourID
}