两次重新加载页面后会话变量变化为什么？

Question

Main.php

<?php
session_start();
msgbox("Are you sure?", "confirm");
$Result = $_SESSION['id'] ;
print "<p id='txt'> </p>";
if($Result == 1 )
    echo "Result is true";
elseif ( $Result == 2 ) 
    print "<br><br>Return value is '$Result'";
function msgbox($msg, $type)
{
    if ($type == "confirm")
    {
        print "<script src='Validate.js'></script>";
        print "<script> ret = confirm ('$msg') ;
        if (ret)
            Write_to_variable('1');
        else
            Write_to_variable('2');
        </script>";
?>

Validate.js

function Write_to_variable( value ) 
{
    if (window.XMLHttpRequest) 
    {
        xmlhttp=new XMLHttpRequest();
    }
    else 
    {
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
            document.getElementById("txt").innerHTML=xmlhttp.responseText;
        }
    }
    xmlhttp.open("GET","Variable.php?id="+value,true);
    xmlhttp.send(); 
}    

Variable.php

<?php
session_start();
if ( $_GET['id'] ) 
{
    $_SESSION['variable'] = $_GET['id'];
    print $_SESSION['variable'];
}
?>

What I am trying to do is,

Getting the value from the javascript confirm box and store return value of confirm box to php SESSION variable using Ajax. In Ajax File I just assigning $_SESSION['id']= $_GET['id']. When the program get execute, I pressed OK from the confirm box. It assign 1 to the session variable of id. If I pressed cancel next time the value doesn't changed, when I am tried to pressed cancel another time, the value of session have changed to id as 2. What is the problem, any suggestions and solution are kindly accepted.

I cant find what is logic hidden behind it. I can clearly see what is returns and what ajax returns but the session variable used in the main.php is changing after second click.

Thanks in Advance.

Answer 1

seems there's nothing wrong just try

1. console log your java script parameters and check for errors

2. use alert and check what what value is passed to the ajax file

3.use die() in your ajax file and check for mismatch.