After you install the pixel track in-page actions, such as product purchases, by tying events to HTML elements such as buttons. For example:

Track In-Page Events

<button onClick="fbq('track', 'Purchase');">Button Text</button>
Or you could create a function that pushes the event. The advantage is if you have multiple HTML elements, you can call a single function when someone clicks any of them; you don't have to define individual onClick element.

For example, to push the event:

<script>
function onClick() {
fbq('track', 'Purchase');
};
</script>

You can call this function to fire Purchase events from multiple HTML elements. For example:

<button onClick="onClick()">Buy Now</button>

<button onClick="onClick()">Buy as a Gift</button>
Note: Pixel Helper may show multiple pixel events firing from the same page. The Pixel Helper expects pages to fire only on load but by tying events to elements, such as a button, you are using an alternative solution that overturns the expected behavior.