Hi i have included client callable in my script include

var EUTSCatalogRITMValidation = Class.create();

EUTSCatalogRITMValidation.prototype = Object.extendsObject(AbstractAjaxProcessor, {

  validateRequestNumber: function(){

  var answer=false;

  var reqNo = this.getParameter('sysparm_req_number');

  var reqDetails = new GlideRecord('sc_req_item');

  reqDetails.addQuery('number',reqNo);

  reqDetails.query();

  //create and return the array of environments

  while(reqDetails.next()){

  return reqDetails.cat_item.name;

  }

  return answer;

  },

  type: 'EUTSCatalogRITMValidation'

});