# Upward scroll

Infinite Ajax Scroll can also be used to load items above the current scroll position. This is useful when you want to load older items first.

*Introduced in Infinite Ajax Scroll 3.1.0*

## Caveats

### Fixed height images

Upward scroll works by calculation screen height and content height. Due to they way browser load content, especially images, this could cause incorrect measurements. This can be solved by using fixed height images.

## Setup

1. Add a previous page link to your pagination.

   ```html
    <div class="pagination">
       <a href="page1.html" class="prev">Prev</a>
       <span class="current">2</span>
       <a href="page3.html" class="next">Next</a>
   </div>
   ```
2. Configure the [`prev`](/reference/options.md#prev) option.

   ```javascript
   // import if you use the NPM package
   import InfiniteAjaxScroll from '@webcreate/infinite-ajax-scroll';

   let ias = new InfiniteAjaxScroll('.container', {
     item: '.item',
     next: '.next',
     prev: '.prev',
     pagination: '.pagination'
   });
   ```

## Hook into upward scroll with events

In this example we notify the user about loading the previous page.

```js
ias.on('prev', function(event) {
  // pageIndex is 0-indexed, so we add 1
  alert(`Page ${event.pageIndex+1} is loading...`);
});
ias.on('preved', function(event) {
    alert(`Page ${event.pageIndex+1} is loaded and prepended to the page.`);
});
```

## Inform user about first page reached

In this example we notify the user when the first page is reached.

```javascript
ias.on('first', () => {
  console.log('User has reached the first page');
})
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.infiniteajaxscroll.com/advanced/upwards.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.