Mortgage Dashboard (PHP + HTML + JS)
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Files
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- index.php      Main page
- styles.css     Styling
- app.js         Calculator logic, dashboard rendering, scenario save/load
- api.php        PHP persistence API
- data/          Folder that stores the JSON file

What this app does
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This rebuilds the Excel worksheet as a browser-based dashboard and adds:
- cleaner input layout
- live monthly mortgage payment calculation
- bridge-loan estimate
- purchase + sale summaries
- saved scenarios that persist on the server
- amortization chart preview

How to install
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1. Upload the entire folder to your PHP-enabled server.
2. Make sure the server can write to the /data folder.
3. Browse to index.php.

Important server permissions
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The PHP process must be able to create and edit:
- data/mortgage_data.json

If saved scenarios do not work:
- check folder permissions on /data
- confirm your host allows file writes from PHP

Suggested permissions
---------------------
Typical Linux hosting:
- folders: 775
- files: 664

How persistence works
---------------------
Saved scenarios are stored in:
- data/mortgage_data.json

No database is required.

Notes about the calculation model
---------------------------------
This version is more complete than the workbook:
- monthly mortgage payment uses principal + interest
- tax, insurance, HOA, and optional PMI are included
- bridge-loan interest can be estimated for a short term
- saved scenarios can be recalled or deleted

Security note
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This version is intentionally simple for public hosting.
If the site is public-facing and many users will access it, add:
- login protection
- CSRF protection
- validation / rate limiting
- backup strategy for the JSON file