Ajax prints output from perl script - Problems with IE7

Question

Here is my javascript code:

var xmlhttp;
var result;
function load()
{
 xmlhttp=null;
 if (window.XMLHttpRequest)
   {// code for IE7+, Firefox, Chrome, Opera, Safari
   xmlhttp=new XMLHttpRequest();
   }
 else
   {// code for IE6, IE5
   xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
   }
 xmlhttp.onreadystatechange=state_Change;
 xmlhttp.open("GET",getLauncherPath,true);
 xmlhttp.send(null);
}

function state_Change()
{
 if (xmlhttp.readyState==3){
  if (xmlhttp.status==200){
   result = "readyState = 3, counting begins\n";
   result += xmlhttp.responseText;
   document.getElementById('T1').innerHTML= result;
  }
 }

 if (xmlhttp.readyState==4){
  // 4 = "loaded"
  if (xmlhttp.status==200)
  {// 200 = "OK"
   document.getElementById('T1').innerHTML= result + "\nreadyState = 4, DONE";
  }
 }
}

Here is my perl code

#!C:/perl/bin/perl.exe

use strict; 
use warnings; 
use CGI; 

$|++; 

my $cgi = CGI->new; 

print $cgi->header, 
      $cgi->start_html("Output Flush Buffer Test"); 

for ( 1..3 ) { 
    print $cgi->p("Line $_"); 
    sleep 1; 
} 

print $cgi->end_html;

Result shows in IE7

undefined readyState = 4, DONE

Result shows in Firefox

readyState = 3, counting begins

Line 1

Line 2

Line 3
readyState = 4, DONE

I got some advice that IE7 doesn't support MIME, that is the reason why IE7 can't flush the output by using state change, is this true? If I run this perl script directly from my IE7 browser, e.g. localhost/cgi-bin/count.pl, IE7 actully shows results line by line with time delay. It is just not working with AJAX.

Please someone help me with this issue, or suggest me a better way to do this.

Answer 1

Johnathon, Thanks for your comment, by checking response text in the same block that print readyState 4.

Result from IE7

undefined 
Line 1

Line 2

Line 3

readyState = 4, DONE

Result from firefox

readyState = 3, counting begins

Line 1

Line 2

Line 3

Line 1

Line 2

Line 3
readyState = 4, DONE

Answer 2

There is alternative way to flush the output in IE7 which I hate to do 1. stdout output into a log file in perl 2. When ajax starts call count, there will be another javascript to call the log file and print the text on the screen.