query.js

var contract_address = '0x10d4b24938f6de7ae4048c7273f09c50d5caf4d9';

module.exports = function() {

  // If using web3 straight away, we need the abi
  var abi = [{"constant":true,"inputs":[],"name":"getCertifiedStudentsCount","outputs":[{"name":"count","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"getTotalBalance","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"newOwner","type":"address"}],"name":"setOwner","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"getQueryFee","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"newBeneficiary","type":"address"}],"name":"setBeneficiary","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"},{"name":"document","type":"bytes32"}],"name":"certify","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"getBeneficiary","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"getCertifierDb","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"}],"name":"isCertified","outputs":[{"name":"isIndeed","type":"bool"}],"payable":true,"type":"function"},{"constant":false,"inputs":[],"name":"withdrawPayments","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"getOwner","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"fixBalance","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"newCertifierDb","type":"address"}],"name":"setCertifierDb","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"document","type":"bytes32"}],"name":"removeCertificationDocumentFromSelf","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"}],"name":"uncertify","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"newQueryFee","type":"uint256"}],"name":"setQueryFee","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"}],"name":"getCertification","outputs":[{"name":"certified","type":"bool"},{"name":"timestamp","type":"uint256"},{"name":"certifier","type":"address"},{"name":"documentCount","type":"uint256"}],"payable":true,"type":"function"},{"constant":false,"inputs":[{"name":"index","type":"uint256"}],"name":"getCertifiedStudentAtIndex","outputs":[{"name":"student","type":"address"}],"payable":true,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"},{"name":"document","type":"bytes32"}],"name":"isCertification","outputs":[{"name":"isIndeed","type":"bool"}],"payable":true,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"},{"name":"index","type":"uint256"}],"name":"getCertificationDocumentAtIndex","outputs":[{"name":"document","type":"bytes32"}],"payable":true,"type":"function"},{"constant":true,"inputs":[{"name":"beneficiary","type":"address"}],"name":"getPaymentOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"document","type":"bytes32"}],"name":"addCertificationDocumentToSelf","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"},{"name":"document","type":"bytes32"}],"name":"addCertificationDocument","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"student","type":"address"},{"name":"document","type":"bytes32"}],"name":"removeCertificationDocument","outputs":[{"name":"success","type":"bool"}],"payable":false,"type":"function"},{"inputs":[{"name":"beneficiary","type":"address"},{"name":"certificationQueryFee","type":"uint256"},{"name":"_certifierDb","type":"address"}],"type":"constructor"},{"payable":true,"type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dest","type":"address"},{"indexed":false,"name":"amount","type":"uint256"}],"name":"LogPaymentReceived","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"previousQueryFee","type":"uint256"},{"indexed":false,"name":"newQueryFee","type":"uint256"}],"name":"LogQueryFeeSet","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"previousBeneficiary","type":"address"},{"indexed":true,"name":"newBeneficiary","type":"address"}],"name":"LogBeneficiarySet","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"previousOwner","type":"address"},{"indexed":true,"name":"newOwner","type":"address"}],"name":"LogOwnerChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"previousCertifierDb","type":"address"},{"indexed":true,"name":"newCertifierDb","type":"address"}],"name":"LogCertifierDbChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"student","type":"address"},{"indexed":false,"name":"timestamp","type":"uint256"},{"indexed":true,"name":"certifier","type":"address"},{"indexed":true,"name":"document","type":"bytes32"}],"name":"LogStudentCertified","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"student","type":"address"},{"indexed":false,"name":"timestamp","type":"uint256"},{"indexed":true,"name":"certifier","type":"address"}],"name":"LogStudentUncertified","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"student","type":"address"},{"indexed":true,"name":"document","type":"bytes32"}],"name":"LogCertificationDocumentAdded","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"student","type":"address"},{"indexed":true,"name":"document","type":"bytes32"}],"name":"LogCertificationDocumentRemoved","type":"event"}];

  // web3.eth.contract(abi).at(contract_address) is the  magic line to get the contract object.
  let contract = web3.eth.contract(abi).at(contract_address);

  contract.getCertifiedStudentsCount((err, res)=>{
    console.log('no. of passed students is '+res.toString());
  });
}