Cannot make call from one php file to another php file - php

Question

I have 3 files: fileNum1.php, fileNum2.php and fileNum3.php.
fileNum1.php file makes a call for fileNum2.php file:
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{
// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","fileNum2.php",false);
xmlhttp.send();
and fileNum2.php makes a call for fileNum3.php:
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{
// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","fileNum3.php",false);
xmlhttp.send();
The call to fileNum3.php is NOT WORKING!
What is the the problem?
(Can it be because I've started new XMLHttpRequest inside existing XMLHttpRequest?)

Answer 1

JavaScript is client-side code. This means that a browser is required to interpret and execute the JavaScript code.
If you access fileNum1.php via a browser, the call to fileNum2.php will execute, as the JavaScript for fileNum1.php is interpreted.
The call from fileNum2.php to fileNum3.php will NOT execute, as it is not returned to the browser. The JavaScript on the 3rd file will be returned as output to the server, which is making the request, and the JavaScript will never make it back to the browser.
If you want an action from fileNum3.php to return to fileNum1.php, you will have to catch the data when fileNum3.php is called on fileNum2.php, and then return the response to fileNum1.php.
Or, you can do it the right way and say if fileNum1.php called fileNum2.php and everything was ok, then call fileNum3.php.
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{
// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET","fileNum2.php",false);
xmlhttp.send();
if(xmlhttp.responseText !== "undefined"){
if (window.XMLHttpRequest)
{
// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp2=new XMLHttpRequest();
}
else
{
// code for IE6, IE5
xmlhttp2=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp2.open("GET","fileNum3.php",false);
xmlhttp2.send();
}