SQL/PHP real-time changes to websites
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How can I allow user input on a page to change the HTML or CSS or anything. Is there a technique for this? I.e. If it is client-side web design, how can I have input from a form moved to a certain page and displayed to replace previous content. Let's say there is a main page with four links: Home, About, Links, Contact. In the admin-edit page, there is a form to enter, edit, delete links. Would I need a SQL database with the links' values that would populate this page and the other? Is there a better way to do this?