Web Server with graphical UI to set LED color

Per a request, I am posting a very simple script that looks for only one text box and sets an LED on Pin 9 to the brightness. This script does NOT use BlinkM I only used that script as a starter for this one.

// Based on
// Small Arduino Webserver --- for BlinkM
// Modified for single text box for brightness
// Jun 7 2012 - Mike Audleman

#include <SPI.h>
#include <Ethernet.h>
#include <Wire.h>
#define maxLength 25

byte mac[] = {
  0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA };
String inString = String(maxLength);

char colorBuff[4];
int val;

EthernetServer server(80);

void setup()
{
  Serial.begin(9600);
  Ethernet.begin(mac);
  server.begin();
}
void loop()
{
  int bufLength;
  EthernetClient client = server.available();
  if (client) {
    boolean current_line_is_blank = true;
    while (client.connected()) {
      if (client.available()) {
        char c = client.read();
        if (inString.length() < maxLength) {
          inString += c;
        }        
        if (c == '\n' && current_line_is_blank) {
          if (inString.indexOf("?") > -1) {
            int Pos_L = inString.indexOf("L");
            int End = inString.indexOf("H", Pos_L);
            if(End < 0){
              End =  inString.length() + 1;
            }
            bufLength = ((Pos_L) - (Pos_L+2));
            if(bufLength > 4){  //dont overflow the buffer
              bufLength = 4;
            }    
            inString.substring((Pos_L+2), (End-1)).toCharArray(colorBuff, bufLength);  //transfer substring to buffer
            val = atoi(colorBuff);
            Serial.print("LED = ");
            Serial.println( val );
            analogWrite(9, val);
          }
          client.println("HTTP/1.1 200 OK");
          client.println("Content-Type: text/html");
          client.println();
          client.println("<html><head></head><body>");
          client.println("<h1>LED - enter values 0 to 255</h1>");
          client.print("<form method=get>LED:<input type=text size=3 name=L value=");
          client.print(val);
          client.print(">&nbsp;<input name=H type=submit value=submit></form>");
          client.println("</body></html>");
          break;
        }
        if (c == '\n') {
          current_line_is_blank = true;
        }
        else if (c != '\r') {
          current_line_is_blank = false;
        }
      }
    }
    delay(1);
    inString = "";
    client.stop();
  }
}