Browser detection with Microsoft AJAX Library

Opera can disguise itself as a MS IE or Mozilla browser (Tools > Preferences | Advanced | Network > Browser Identification). This feature lets Opera "slip through" cases where access to a website is restricted to IE or Mozilla browsers.

I noticed that while Peter-Paul Koch's browser detection script correctly identifies Opera even if a fake browser id is set, it is misreported by the Microsoft AJAX Client Library due to the way the browser detection code is implemented in MicrosoftAjax.js.

Related: HOW TO precisely detect the browser version for IE 5 or higher

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