Currently, I am in the process of developing a real estate website that utilizes a paid service for displaying real estate listings. The unique aspect of this setup is that my website operates as a subdomain of the main listings website, resulting in a URL like www.mywebsite.listingswebsite.com. Essentially, the listings website takes my header and footer wrappers and merges them with their content in the middle of the page.
My Header
Their listings content that I have no control over
My Footer
However, an issue arises when I desire to make modifications to the displayed page. Ideally, I would like to insert additional content before their provided elements, rearrange items on the page, and even remove certain elements. Currently, my knowledge extends solely to removing elements from the page by targeting their Div ID and using "display: none" in my CSS file.
Yet, what if I wish to add content to the page? Given that I only have access to CSS/JS, how would I be able to achieve this task? For instance, imagine I want to include an image right before their existing content - how could this be accomplished?