//taken from http://icant.co.uk/sandbox/datatable-to-chart/index.html
var hideClass = 'hidden';
var chartColor = '339933';
var chartSize = '450x150';
  
var toTableClass = 'totable';
var tableClass = 'generatedfromchart';

var t = document.getElementById('suscripciones');;
var c = t.className;
var data = [];
var labels = [];
var charturl = 'http://chart.apis.google.com/chart?cht=lc&chxt=x,y&chco=' + chartColor + '&chs=' + chartSize + '&chd=t:';
var tds = t.getElementsByTagName('tbody')[0].getElementsByTagName('td');
var max = tds[1].innerHTML;

for(var j=0;tds[j];j+=2){
  var blog = tds[j].getElementsByTagName('a')[0].innerHTML;
  labels.push( blog );
  var este_numero = dosdecimales ( tds[j+1].innerHTML*100.0/max) ;
  data.push(este_numero);
 };

var chart = document.createElement('img');
chart.setAttribute('src',charturl+data.join(',') + '&chxl=0:|' + labels.join('|')+'|1:||'+max);
chart.setAttribute('alt',t.getAttribute('summary'));
t.parentNode.insertBefore(chart,t);

function dosdecimales ( num ) {
  return Math.round( num*100 )/100;
}