function changeTags(e){
	
	if(typeof  e.nodeType == "undefined"){
	var obj = getTarget(e); 
	}else{ 
	var obj = e;
	}
	obj.className ='on';
	
 	var categories = document.getElementById('categories');
	if(categories.old_obj)categories.old_obj.className ='off';
	
	switch(obj.id){
	case 'cat_click':str_url = '/category/'; str_class='';break;
	case 'tec_click':str_url = 'http://www.technorati.com/tag/';str_class='tec';break;
	case 'del_click':str_url = 'http://del.icio.us/matpol/';str_class='del';break;
	default:str_url = '/category/';str_class='';break;
	}
	
	
	for (var i = 0; i <= categories.childNodes.length-1; i++){
	var obj_node = categories.childNodes[i];
	
	 if(obj_node.tagName == 'A'){
	
		var arr_href = obj_node.getAttribute('href').split('/');
        var str_cat = arr_href[arr_href.length-2]; 
		var str_path =  str_url+str_cat+'/';
		obj_node.setAttribute('href', str_path);
		obj_node.className = str_class;
	 
	 }
	
	}
	categories.old_obj = obj;
	}
	
	
	
function attachEventListener(target, eventType, functionRef,capture)
{
 if (typeof target.addEventListener != "undefined")
 {
   target.addEventListener(eventType, functionRef, capture);
 }
 else if (typeof target.attachEvent != "undefined")
 {
   target.attachEvent("on" + eventType, functionRef);
 }
 else
 {
   eventType = "on" + eventType;

   if (typeof target[eventType] == "function")
   {
     var oldListener = target[eventType];

     target[eventType] = function()
     {
       oldListener();

       return functionRef();
     };
   }
   else
   {
     target[eventType] = functionRef;
   }
 }
}
//attachEventListener(window, "load", initload, false);

function initload(){
arr_tags = ['cat_click','tec_click','del_click'];
for (var i = 0; i <= arr_tags.length-1; i++){
obj = document.getElementById(arr_tags[i]);
attachEventListener(obj, "click", changeTags, false);
}

obj_init = document.getElementById('cat_click');
changeTags(obj_init);
}

function getTarget(e)
{
	var targ;
	if (!e) var e = window.event;
	if (e.target) targ = e.target;
	else if (e.srcElement) targ = e.srcElement;
	if (targ.nodeType == 3) // defeat Safari bug
		targ = targ.parentNode;
		
		return targ;
}