function conf_markdown_textarea(div_id){
//setup
var textarea = new Control.TextArea(div_id);
var toolbar = new Control.TextArea.ToolBar(textarea);
toolbar.container.id = 'markdown_toolbar'; //for css styles
//preview of markdown text
 var converter = new Showdown.converter;
 var converter_callback = function(value){
 $('markdown_formatted').update(converter.makeHtml(value));
 }
 converter_callback(textarea.getValue());
 textarea.observe('change',converter_callback);

 //buttons
 toolbar.addButton('Italics',function(){
 this.wrapSelection('_','_');
 },{
 id: 'markdown_italics_button'
 });

 toolbar.addButton('Bold',function(){
 this.wrapSelection('**','**');
 },{
 id: 'markdown_bold_button'
 });
 
 toolbar.addButton("Link",function(){
 this.wrapSelection('+','+');
 },{
 id: 'markdown_link_button'
 });

 
 }