function convertHTML(str) {
  // create an object with key:value pair as char:HTML entities
  var htmlConv = {"&":"&", "<":"<", ">": ">",'\"':""","\'":"&apos;" };
  for (var key in htmlConv){
    str=str.replace(new RegExp(key,"g"), htmlConv[key]);

  }
  return str;
}
convertHTML('Stuff in "quotation marks"');