function leftBack(stringToSearch,subString) {
  if (stringToSearch.indexOf(subString)==-1)
    return stringToSearch;
  var sourceStringBack = '';
  var searchStringBack = '';
  var back = '';
  var result = '';
  var length = stringToSearch.length;
  for (var i=length; i>0; i--) {
    sourceStringBack=sourceStringBack+stringToSearch.substr(i-1,1);
  }
  var length=subString.length
  for(var i=length; i>0; i--) {
    searchStringBack=searchStringBack+subString.substr(i-1,1);
  }
  var pos=sourceStringBack.indexOf(searchStringBack)+searchStringBack.length;
  var length=sourceStringBack.length;
  var start=length-pos;
  result=sourceStringBack.substr(length-start,start)
  var length=result.length
  for (var i=length; i>-1; i--) {
    back=back+result.substr(i,1)
  }
  return(back);
}
function rightBack(stringToSearch,subString) {
  if (stringToSearch.indexOf(subString)==-1)
    return stringToSearch;
  var sourceStringBack = '';
  var searchStringBack = '';
  var back = '';
  var result = '';
  var length = stringToSearch.length;
  for (var i=length; i>0; i--) {
    sourceStringBack=sourceStringBack+stringToSearch.substr(i-1,1);
  }
  var length=subString.length
  for(var i=length; i>0; i--) {
    searchStringBack=searchStringBack+subString.substr(i-1,1);
  }
  var pos=sourceStringBack.indexOf(searchStringBack)
  result=sourceStringBack.substr(0,pos)
  var length=result.length
  for (var i=length; i>-1; i--) {
    back=back+result.substr(i,1)
  }
  return(back);
}