How to get all selected values from ?

Unless a question asks for JQuery the question should be first answered in standard javascript as many people do not use JQuery in their sites.

From RobG How to get all selected values of a multiple select box using JavaScript?:

  function getSelectValues(select) {
  var result = [];
  var options = select && select.options;
  var opt;

  for (var i=0, iLen=options.length; i<iLen; i++) {
    opt = options[i];

    if (opt.selected) {
      result.push(opt.value || opt.text);
    }
  }
  return result;
}