DocumentationExperience PlatformWeb SDK Guide

Using top and bottom of page events in Web SDK

November 21, 2023
  • Topics:
  • Web SDK

CREATED FOR:

  • Developer

When you want to deliver personalized experiences to your customers, a web page’s loading time is essential.

To optimize the loading times and deliver personalization as quickly as possible, Web SDK supports the configuration of top and bottom of page events.

Top and bottom of page events describe a method of asynchronously loading various elements in the page, while keeping the page load time at a minimum.

This configuration minimizes the amount of time a user has to wait until the personalized content is loaded.

In terms of metrics accuracy, Adobe Analytics can ignore top of page events, which leads to more accurate metrics recording, since only one page hit is recorded (the bottom of page event).

Use cases

A sports apparel retailer wants to deliver personalized experiences to their shoppers, while minimizing user friction when visiting their website, all while being able to accurately collect visitor metrics.

By using top and bottom of page events in Web SDK, the marketing team can configure their personalization delivery in the most optimal way:

  • Web SDK sends a personalization request which is loaded as soon as the page begins to load. This is a top of page event.
  • When the page finishes loading, a page view event is recorded. This happens later in the page loading process. This is a bottom of page event.

Top of page event example

The code sample below exemplifies a top of page event configuration which requests personalization but does not send display events for automatically rendered propositions. The display events will be sent as part of the bottom-of-page event.

Top of page event
alloy("sendEvent", {
  type: "decisioning.propositionFetch",
  renderDecisions: true,
  personalization: {
    sendDisplayEvent: false
  }
});
Paramter
Required/Optional
Description
type
Required
Set this parameter to decisioning.propositionFetch. This special event type tells Adobe Analytics to drop this event. When using Customer Journey Analytics, you can also set up a filter to drop these events.
renderDecisions
Required
Set this parameter to true. This parameter tells Web SDK to render decisions returned by the Edge Network.
personalization.sendDisplayEvent
Required
Set this parameter to false. This stops display events from being sent.

Bottom of page event examples

Auto-rendered propositions

The code sample below exemplifies a bottom of page event configuration which sends display events for propositions which were automatically rendered on the page but for which display events were suppressed in top of page event.

NOTE
In this scenario, you must call the bottom of page event after the top of page one. However, the bottom of page event does not need to wait until the top of page one has completed.
alloy("sendEvent", {
  personalization: {
    includeRenderedPropositions: true
  },
  xdm: { ... }
});
Paramter
Required/Optional
Description
personalization.includeRenderedPropositions
Required
Set this parameter to true. This enables the sending of display events which were suppressed in the top of page event.
xdm
Optional
Use this section to include all the data you need for the bottom of page event.
Manually rendered propositions

The code sample below exemplifies a bottom of page event configuration which sends display events for propositions which were manually rendered on the page (i.e. for custom decision scopes or surfaces).

NOTE
In this scenario, the bottom of page event must wait until the top of page event has completed, to render the propositions and record the bottom of page event.
alloy("sendEvent", {
  xdm: {
    ... // Optional bottom of page event data
    _experience: {
      decisioning: {
        propositions: propositions.map(function(p) {
          return {
            id: p.id,
            scope: p.scope,
            scopeDetails: p.scopeDetails
          };
        }),
        propositionEventType: {
          display: 1
        }
      }
    }
  }
});
Paramter
Required/Optional
Description
xdm._experience.decisioning.propositions
Required
This section defines the manually rendered propositions. You must include the proposition ID, scope, and scopeDetails. See the documentation on how to manually render personalization for more information on how to record display events for manually rendered content. Manually rendered personalization content must be included in the bottom of page hit.
xdm._experience.decisioning.propositionEventType
Required
Set this parameter to display: 1.
xdm
Optional
Use this section to include all the data you need for the bottom of page event.

Single-page application with top and bottom page hits

First page view

The example below includes the addition of the required xdm.web.webPageDetails.viewName parameter. This is what makes it a single-page application. The viewName in this example is the view which is loaded on the page load.

// Top of page, render decisions for the "home" view.
alloy("sendEvent", {
    type: "decisioning.propositionFetch",
    renderDecisions: true,
    personalization: {
        sendDisplayEvent: false
    },
    xdm: {
        web: {
            webPageDetails: {
                viewName: "home"
            }
        }
    }
});

// Bottom of page, send display events for the items that were rendered.
// Note: You need to include the viewName in both top and bottom of page so that the
// correct view is rendered at the top of the page, and the correct view is recorded
// at the bottom of the page.

alloy("sendEvent", {
    personalization: {
        includeRenderedPropositions: true
    },
    xdm: {
        ...,
        web: {
            webPageDetails: {
                viewName: "home"
            }
        }
    }
});
Second page view (Option 1)

In this example there is no need to do a top/bottom of page split because the personalization for the page has already been fetched.

alloy("sendEvent", {
  renderDecisions: true,
  xdm: {
    ...,
    web: {
      webPageDetails: {
        viewName: "cart"
      }
    }
  }
});
Second page view (Option 2)

If you still need to delay the bottom of page hit, you can use applyPropositions for the top of page hit. Since no personalization needs to be fetched and no Analytics data needs to be recorded, there is no need to make a request to the Edge Network.

// top of page, render the decisions already fetched for the "cart" view.
alloy("applyPropositions", {
    viewName: "cart"
});

// bottom of page, send display events for the items that were rendered.
// Note: You need to include the viewName in both top and bottom of page so that the
// correct view is rendered at the top of the page, and the correct view is recorded
// at the bottom of the page.
alloy("sendEvent", {
    personalization: {
        includeRenderedPropositions: true
    },
    xdm: {
        ...,
        web: {
            webPageDetails: {
                viewName: "cart"
            }
        }
    }
});

GitHub sample

The sample found at this address demonstrates how to use Experience Platform and Web SDK to request personalization at the top of the page, and send analytics metrics at the bottom. You can download the sample and run it locally to understand how top and bottom of page events work.

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