Simon Willison’s Weblog

Magic properties make Firefox synchronously load the Java plugin. Even defining a function called sun() (or several other symbols) will trigger the Java VM to be loaded, dramatically hurting the performance of your page.

Posted 27th February 2009 at 4:03 pm

Recent articles

First impressions of Claude Cowork, Anthropic's general agent - 12th January 2026
My answers to the questions I posed about porting open source code with LLMs - 11th January 2026
Fly's new Sprites.dev addresses both developer sandboxes and API sandboxes at the same time - 9th January 2026

firefox 90 java 90 javascript 732 mark-pilgrim 85 performance 94

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