How to add new button to order view in Magento admin panel?

Question

How to add custom button to order view page near \"Back\" and \"Edit\"?

Answer 1

config.xml:

    
         
            
                Namespace_Module_Block_Adminhtml_Sales_Order_View
            
        
    
 

Namespace/Module/Block/Adminhtml/Sales/Order/View.php:

class Namespace_Module_Block_Adminhtml_Sales_Order_View extends Mage_Adminhtml_Block_Sales_Order_View {
    public function  __construct() {

        parent::__construct();

        $this->_addButton('button_id', array(
            'label'     => Mage::helper('xxx')->__('Some action'),
            'onclick'   => 'jsfunction(this.id)',
            'class'     => 'go'
        ), 0, 100, 'header', 'header');
    }
}