Google Analytics | How do I see previous page views? – ChannelMix

Purpose

This article will demonstrate how to capture previous page (referrer) data, and make it available in Google Analytics reports.

This may be especially useful if you have destination-based triggers.

Example scenario: tracking page views of a /thank-you page. Sometimes we do not know all of the ways a User may arrive at the page so we need to collect data on the preceding page(s) for debugging. Or we may wish to fire a tag only when Users arrive from a specific page.

Demonstrated below are two Variables that may be implemented via GTM as a solution.

Previous Page - for basic debugging and trigger conditions
Previous Page Stack - collect data on multiple pages for advanced debugging

Previous Page Variable

For the basic Previous Page Variable,

create a JavaScript Variable via GTM
add the variable as a Custom Dimension to a Tag

Variable

Copy/paste the code below into a JavaScript Variable in GTM.

document.referrer

Tag - GA4 Configuration

In order to view Previous Page in GA4 reports, the custom dimension should be configured as below.

In GA4, navigate Configure > Custom definitions > Create custom dimensions

Tag - GTM Configuration

Add the Previous Page Variable to a Tag as an Event Parameter. Your tag may be of any type but usually a page view tag makes the most sense.

GA4 Reports

The two configuration steps above make the previous_page parameter available in your GA reports. For the given Tag (in this case, page_view), we see the page a User was on immediately before the Tag fired.

Previous Page Variable as a Trigger Condition

You may have a trigger that should fire on a page view of /thank-you but only with to fire when Users come from a specified page. If you have the Previous Page Variable you may add it as a Trigger condition as demonstrated below:

Previous Page Stack

Through this implementation, we will create a string to store page paths in browsers Session Storage. Then we will retrieve that value with a Custom JavaScript Variable and pass it to Google Analytics via Tag.

Custom HTML Tag - to store previous page values

In GTM create a Custom HTML Tag and copy/paste the following code:

<script>
  var stack_limit = 3; // how may page paths to store
  var stored_stack = "previous_page_stack";
   
  if (sessionStorage.getItem(stored_stack)) {
   
    // retrieve the stored stack
    var stackArray = sessionStorage.getItem(stored_stack).split("|");
   
    for (var i = 0; i < stackArray.length; i++) {
      if (stackArray[i] === "" || stackArray[i] == "undefined" ) {
        stackArray.splice(i, 1);
      }
    }
     
    // add the current page path
    stackArray.push(document.location.pathname);
   
    // manage the length of the stack according to the stack_limit
    if (stackArray.length > stack_limit) { stackArray.shift(); }
   
    // convert to string and store
    sessionStorage.setItem(stored_stack, stackArray.join("|"));

  } else {
    sessionStorage.setItem(stored_stack, "home");
  }
</script>

Custom JavaScript Variable - to retrieve stored values

In GTM create a Custom JavaScript Variable and copy/paste the following code:

function() { return sessionStorage.getItem("previous_page_stack"); }

previous_page_stack

The value stored in Session Storage and returned by the previous_page_stack Variable looks like this:

home|/platform/dashboard-templates/|/lets-talk/

Where page paths are added to the string, separated by "|".

The stack_limit variable included in the script limits the number of page paths included in this string and may be adjusted as needed. With the limit of 3 set, the next page view will delete the oldest page path ("home") from the string to add the latest, keeping no more than three at a time.

Previous Page Stack Conclusion

At this point, you may add this Variable to any Tag as a Custom Dimension, as previously demonstrated with the Page View Variable. You may want to do this in order to see how any User arrived at a page or conversion. At times there may be edge cases where Users unexpectedly arrive at a site location. You can use this variable to help understand those interactions.

In this Article