How to load data in a combobox without reloading the page from other page in PHP

Write the code in page a.php

<select name="company_id" id="company_id" >

                                                   <option></option>

                                                  

                                                   <?php

                                                   $getCompany = "select customer_id, company_name from customer WHERE customet_type = 1";

                                                   $getCompanyResult = mysql_query($getCompany);

                                                   while($getCompanyRows = mysql_fetch_object($getCompanyResult)){

                                                   ?>

                                                   <option value="<?php echo $getCompanyRows->customer_id ; ?>" <?php if($getCompanyRows->customer_id == $var->company_id){ echo "selected"; } ?> ><?php echo $getCompanyRows->company_name ; ?></option>

                                                  

                                                   <?php

                                                   }

                                                   ?>

                                                   </select>

<a href="#" onClick="window.open('b.php?hide_menu=1','popup','width=960,height=530,scrollbars=no,scrollbars=yes,toolbar=no,directories=no,location=no,menubar=no,status=no,left=300,top=300'); return false">Add New Data</a>

In Page B:

Write some code to insert the data in database.

<script language="javascript">

//alert(window.opener.document.getElementById('company_id').value);

var optionstr = '<option></option>';

   <?php

   $getCompany = "select customer_id, company_name from customer WHERE customet_type = 1";

   $getCompanyResult = mysql_query($getCompany);

   while($getCompanyRows = mysql_fetch_object($getCompanyResult)){

   ?>

   optionstr +='<option value="<?php echo $getCompanyRows->customer_id ; ?>"><?php echo $getCompanyRows->company_name ; ?></option>';

   <?php

   }

   ?>

window.opener.document.getElementById('company_id').innerHTML= optionstr;

</script>