gistfile1.js

$("#marketList tbody.yui-dt-data")
  .find('tr')
  .map(function(_,row){
    var $r = $(row);
    var data = {
      "name": $r.find(".yui-dt-col-market").text()
      , "sell": parseFloat($r.find(".yui-dt-col-sell").text())
      , "buy": parseFloat($r.find(".yui-dt-col-buy").text())
    };
    return data;
  });