Q:

PHP Page content loads from cache when loading same page multiple times

I am displaying shopping cart products by reading session variables.
If a product is added in a page1 , I am setting session array variable. after navigating to 
page2 i am loading the session content to display the product in shopping cart in page2.
Then if i add any product in page2 then going to page1 , the page1 is not showing refreshed content, instead it takes content from page1 cache. 

But when i do F5 or CTRL+F5, it works fine...

I want the page not to load from cache everytime when i visit even if it is same page.
Here is my code:
<?php 
    echo "<script>
    $(document).ready(function() {";
    echo "add1('".$session_variable."')";
    echo "});</script>";
?>
<script>
add1(item)
{
document.getElementById('ItemName').value=item;
}
<script>

EDIT: I navigate from Page 1 to Page2 using onclick event as below..
<a onclick="window.location='page2.php'" style="text-decoration:none">Page2</a><br>
<a onclick="window.location='page1.php'" style="text-decoration:none">Page1</a><br>

I added following lines, But no use.
<META HTTP-EQUIV="Pragma" CONTENT="no-cache,must-revalidate">
<META HTTP-EQUIV="Expires" CONTENT="-1">

A:

How do you navigate back to back one, do you have a url that is clicked that navs back or do you use window.history.back()?
If you are using javascript to nav back then that may be the issue.  When navigating back to page 1 use a url with a cache break at the end of it like so
window.location.href = "/page1.php?cb=" + Math.random();

