how to filter the products using code

<?php

$val=$_GET['advertiser_id'];

$collection = Mage::getModel('catalog/product')->getCollection()
->addAttributeToSelect('*') // select all attributes
->setPageSize(30) // limit number of results returned
->setCurPage(4) // set the offset (useful for pagination)
->addAttributeToFilter('advertiser_name', array('finset' => $val));

// we iterate through the list of products to get attribute values
?>

<!--============================container-fluid=========================-->

<div class="item-main container-fluid">
    <?php //echo $this->getPagerHtml(); ?>
<div class="row">
<?php
foreach ($collection as $product) {
  ?>
  <div class="col-md-2">
      <div class="border01">
  <a href="<?php echo $product->getProductUrl(); ?>"><img src="<?php echo Mage::getBaseUrl(Mage_Core_Model_Store::URL_TYPE_MEDIA).'catalog/product'.$product->getImage(); ?>"/></a>
 <div class="item-text1"> <?php  echo $product->getName();?></div>
  </div>
  </div>
  <?php
}
?>