To make several pop-ups like when this page loaded you can add more alert tags like this.

You can also make the pop-up start with a link. The link can be text, a button or even an image.

Here is a Clickable textlink. and here is a Mouseover text link.

And here is a form button

You can also use an alert to give your visitors a little message about the link they are going to. This link will simply reload this page so you can scroll back down to see how it is done. You will notice that there is a forward slash before the apostrophe in this alert, this is done so the browser knows the apostrophe is not part of the JavaScript code.

Alert Pop-up

Here is the exact code used for the link above.