Add wysiwyg editor in custom magento module.

Just Follw this simple 4 steps in your custom module.
step-1
Go to following path and open Edit.php
app\code\local\Namespace\Modulename\Block\Adminhtml\Modulename
and Add this Function
protected function _prepareLayout()
{
// Load Wysiwyg on demand and Prepare layout
if (Mage::getSingleton(‘cms/wysiwyg_config’)->isEnabled() && ($block = $this->getLayout()->getBlock(‘head’))) {
$block->setCanLoadTinyMce(true);
}
parent::_prepareLayout();
}

step-2
Go to following path and open Form.php
app\code\local\Namespace\Modulename\Block\Adminhtml\Modulename\Edit\Tab
and find function protected function _prepareForm()
and add
$form->setHtmlIdPrefix(‘modulename’);
$wysiwygConfig = Mage::getSingleton(‘cms/wysiwyg_config’)->getConfig(
array(‘tab_id’ => ‘form_section’)
);
And add field property
$wysiwygConfig["files_browser_window_url"] = Mage::getSingleton(‘adminhtml/url’)->getUrl(‘adminhtml/cms_wysiwyg_images/index’);
$wysiwygConfig["directives_url"] = Mage::getSingleton(‘adminhtml/url’)->getUrl(‘adminhtml/cms_wysiwyg/directive’);
$wysiwygConfig["directives_url_quoted"] = Mage::getSingleton(‘adminhtml/url’)->getUrl(‘adminhtml/cms_wysiwyg/directive’);
$wysiwygConfig["widget_window_url"] = Mage::getSingleton(‘adminhtml/url’)->getUrl(‘adminhtml/widget/index’);
$wysiwygConfig["files_browser_window_width"] = (int) Mage::getConfig()->getNode(‘adminhtml/cms/browser/window_width’);
$wysiwygConfig["files_browser_window_height"] = (int) Mage::getConfig()->getNode(‘adminhtml/cms/browser/window_height’);
$plugins = $wysiwygConfig->getData(“plugins”);
$plugins[0]["options"]["url"] = Mage::getSingleton(‘adminhtml/url’)->getUrl(‘adminhtml/system_variable/wysiwygPlugin’);
$plugins[0]["options"]["onclick"]["subject"] = “MagentovariablePlugin.loadChooser(‘”.Mage::getSingleton(‘adminhtml/url’)->getUrl(‘adminhtml/system_variable/wysiwygPlugin’).”‘, ‘{{html_id}}’);”;
$plugins = $wysiwygConfig->setData(“plugins”,$plugins);
$fieldset->addField(‘fieldname’, ‘editor’, array(
‘name’ => ‘fieldname’,
‘label’ => Mage::helper(‘modulename’)->__(‘Content’),
‘title’ => Mage::helper(‘modulename’)->__(‘Content’),
‘style’ => ‘width:700px; height:300px;’,
‘wysiwyg’ => true,
‘required’ => false,
‘state’ => ‘html’,
‘config’ => $wysiwygConfig,
));

step-3
Go to following path and open modulename.xml if its not available than create id
app\design\adminhtml\default\default\layout
and add
<?xml version=”1.0″?>
<layout>
<modulename_adminhtml_controllername_index>
<reference name=”content”>
<block type=”modulename/adminhtml_blockname” name=”blockname” />
</reference>
</modulename_adminhtml_controllername_index>
<modulename_adminhtml_controllername_edit>
<update handle=”editor”/>
</modulename_adminhtml_controllername_edit>
</layout>

step-4
if you want to Display editor's content in front side use below code .

$_cmsHelper = Mage::helper(‘cms’);
$_process = $_cmsHelper->getBlockTemplateProcessor();
echo $_process->filter($item['content']);