Magento: Rma extension list page search functionality

1. Add a search box field in your page collection:

<div class="rma-search">
        <form action="<?php echo $this->getUrl('returns/rma/')?>" method="post">
            <input type="text" name="order_increment_id" placeholder="Search by order number"/>
            <input type="submit" name="action" value="Search"/>
        </form>
    </div>

For listing as you can see there is a foreach loop for collection Like:

so you need to find out the collection location like in my case i found:

$collection = $this->getRmaCollection();

and the collection of function i found in list.php page Like:

Original code:

public function getRmaCollection()
    {
        if (!$this->_collection) {
            $this->_collection = Mage::getModel('rma/rma')->getCollection()
                ->addFieldToFilter('main_table.customer_id', $this->getCustomer()->getId())
                ->setOrder('created_at', 'desc');
            if ($order = $this->getOrder()) {
                $this->_collection->addFieldToFilter('order_id', $order->getId());
            }
        }

        return $this->_collection;
    }

For Search functionality modified code

public function getRmaCollection()
    {
        $ordId = $this->getRequest()->getParam('order_increment_id');
        
        if($ordId){
            $ord  = Mage::getResourceModel('sales/order_collection')
                    ->addFieldToSelect('*')
                    ->addAttributeToFilter('increment_id',array('like'=>'%'.$ordId.'%'))
                    ->addFieldToFilter('customer_id', Mage::getSingleton('customer/session')->getCustomer()->getId());
            foreach($ord as $o)
            {
                $ordIdNew[] = $o->getId();
            }
            if (!$this->_collection) {
                $this->_collection = Mage::getModel('rma/rma')->getCollection()
                ->addFieldToFilter('main_table.customer_id', $this->getCustomer()->getId())
                ->addFieldToFilter('main_table.order_id', array('in'=>$ordIdNew));
            }
        }
        else{
            if (!$this->_collection) {
                $this->_collection = Mage::getModel('rma/rma')->getCollection()
                    ->addFieldToFilter('main_table.customer_id', $this->getCustomer()->getId())
                    ->setOrder('created_at', 'desc');
                if ($order = $this->getOrder()) {
                    $this->_collection->addFieldToFilter('order_id', $order->getId());
                }
            }
        }
        return $this->_collection;
        
    }