Custom code for embedded web application HTML

I have a website that is very simple, this job is split into two parts.

Part 1: I have some code that runs when I click a button, then the page changes the URL and height of the embedded webframe. I need this to happen on page load not when the button is clicked.

Part 2: I have some urls that populate the text of some buttons. I need to set the hyperlink of the button to each url individually using IDs of the button that I have already added. The links need to open in a new tab