pro.js

function xhr(url,callback){
	var x = new XMLHttpRequest();
	x.onload = function(){
		callback(x.response);
	}
	x.open('GET',url);
	x.responseType = 'document';
	x.send();
}

var sum = 0;
var pro = 0;
var c = 0;

var callback = function(document){
	var element = document.getElementById('item-list');
	var elements = element.getElementsByClassName('list nozebra')[0].getElementsByTagName('li');
	sum += elements.length;
	for(i=0;i<elements.length;i++)
		if(elements[i].getElementsByClassName('icon-pro').length)
			pro++;
	c++;
	var next = element.getElementsByClassName('more-blogs more');
	if(next.length && c < 1)
		xhr(next[0].getElementsByTagName('a')[0].href,callback);
	else
		alert('はてなブログ：'+(sum-pro)+'\nはてなブログPro：'+pro+'\n総エントリー数：'+sum);
}

xhr('http://blog.hatena.ne.jp/-/recent',callback);