getDataFromClasses(elm, identifier)

getDataFromClasses.js

var getDataFromClasses = function(elm, identifier){
  var classes = jQuery(elm).attr('class').split(' '),
      data = '',
      regex = new RegExp(identifier);
  // Loop though classes
  for(var i = 0; i < classes.length; i++){
    // If current class matches the identifier, extract data
    if(regex.test(classes[i])){
      data = classes[i].replace(identifier, '');
      break;
    }
  }
  // Return data
  return data;
};