Why do browsers allow cross-domain JavaScript to execute but not XMLHttpRequests?
7th December 2010
My answer to Why do browsers allow cross-domain JavaScript to execute but not XMLHttpRequests? on Quora
It’s called the Same Origin Policy, and it’s principally about intranets. Imagine you have a URL http://intranet.corp/top-secret-...—and you then visit http://evil.example.com/ . If cross domain XHR was allowed the evil site could suck that secret document off your intranet without you realising.
JavaScript should really have the same restrictions (I shouldn’t be able to load http://intranet.corp/top-secret-... ) but as I understand it no one spotted the problem until the entire Internet economy was already dependent on externally hosted scripts as a business model.
More recent articles
- Slop is the new name for unwanted AI-generated content - 8th May 2024
- Weeknotes: more datasette-secrets, plus a mystery video project - 7th May 2024
- Weeknotes: Llama 3, AI for Data Journalism, llm-evals and datasette-secrets - 23rd April 2024
- Options for accessing Llama 3 from the terminal using LLM - 22nd April 2024
- AI for Data Journalism: demonstrating what we can do with this stuff right now - 17th April 2024
- Three major LLM releases in 24 hours (plus weeknotes) - 10th April 2024
- Building files-to-prompt entirely using Claude 3 Opus - 8th April 2024
- Running OCR against PDFs and images directly in your browser - 30th March 2024
- llm cmd undo last git commit - a new plugin for LLM - 26th March 2024
- Building and testing C extensions for SQLite with ChatGPT Code Interpreter - 23rd March 2024