We can process multiple dropdown select using array concept.
Please refer the below example code.
<?php if(isset($_POST['submit'])) { $product=$_POST['product']; //print_r($product); $count=count($product); for($i=0;$i<$count;$i++){ echo $product[$i]."<br>"; } } ?> <form action="#" method="post"> <select name="product[]" multiple="multiple"> <option value="product1">product1</option> <option value="product2">product2</option> <option value="product3">product3</option> </select> <input name="submit" type="submit" /> </form>