Displaying info from website2 on website1 using Javascript

Sorry if the title sounds a bit silly, but this is what I’d like to do.

I have a page on a site, e.g.
http://jimpix.co.uk/ecards/no-adverts.asp

And I’d like to display on that site, some info taken from this page:
http://www.justgiving.com/jimpix-advert-free

The 2 bits of info I’d like to display on the jimpix.co.uk site is the total raised, and the number of donations.

That info is held in the following HTML snippet on the justgiving site:

<div class="no-print">
    <p><span class="raised-so-far">£436.00</span> <em> raised
    </em></p>
    <p><span class="number-of-donations">48</span> <em>donations</em></p>
</div>

I’ve used JavaScript in the past to store the data held in a chunk of HTML via something like e.g.

var num_total = document.getElementsByClassName('raised-so-far');
var num_donations = document.getElementsByClassName('number-of-donations');

But I’ve only ever done that when the javascript is running on the same page I’m trying to pull data from.

I wondered how I could go about doing it if the site I’m working on is jimpix.co.uk, but the site I want to pull the data from is justgiving.com?

Any advice would be much appreciated.

Thanks!

The best way would be to use the API

That is scraping data.

You can use CURL.

But be sure you have the permission.

True enough. But it seems to me if the API is used that permission is implied, no?
Not only that, but I think it would be more efficient to get what info you want directly rather than parsing it out of web pages.