A Google App Script function (javascript) to check if an IP address belongs to a given range.

is-in-range.gs

function isInRange(ip, firstRangeIp, lastRangeIp)
{ 
  var ipArr = ip.split("."); 
  var firstArr = firstRangeIp.split(".");
  var lastArr = lastRangeIp.split(".");
  
  var pos = 0
  
  for(i=0;i<4;i++)
  {
    
    if(Number(ipArr[i])<Number(firstArr[i]))
      return false;
    else if (Number(ipArr[i])==Number(firstArr[i])) pos=i;
    else{
      if(Number(ipArr[pos+1])>Number(lastArr[pos+1])) 
      return false;
    }

  }
  return true;
}