Download websites that use Microsoft Ajax Content Delivery Network

About Microsoft Ajax Content Delivery Network

The name promises a content delivery network, which sounds like something a site owner bought. Nothing here was ever bought. Loading a library from these addresses cost nothing and committed nobody, which is why the tags spread so easily and why they were then forgotten.

Microsoft Ajax Content Delivery Network is a CDN operated by Microsoft that serves common browser libraries from a fixed set of URLs. A developer pasted a script tag pointing at it, the visitor's browser fetched a copy of jQuery or a validation library from Microsoft's servers instead of from the site's own, and the reference stayed in the template for as long as the template lived. The service dates to 2010 and is Proprietary, which means the endpoints exist at the operator's discretion and not under any community guarantee.

A reference to it on a page crawled in October 2026 is mostly an age signal. Loading shared libraries from a public endpoint made sense while browsers kept one cache across all sites and a visitor might arrive with the file already downloaded from somewhere else. Cache partitioning ended that argument, and current projects bundle their dependencies instead. A page still pointing at this endpoint is usually a page whose front end was assembled in an earlier era and never rebuilt, and in practice it sits beside an older Microsoft server stack, older markup conventions and a design that has aged with it.

The audience for a list like this is anyone whose product is modernisation. Agencies pitching rebuilds, front-end tooling vendors, and consultancies whose offer is migrating legacy application stacks all want the population rather than examples. Security and risk teams want it too, for a different reason. An external script tag is an execution dependency on infrastructure somebody else controls, and a reference that stops resolving leaves a page quietly broken in ways nobody on the site is monitoring.

As of October 2026 we detect the reference on 22,848 sites, 11,117 of them resolving to United States, with .com carrying more than any other suffix. Concentration in one market is what you would expect from a stack adopted through enterprise development tooling rather than through open source communities, though hosting and registration also pull the country column toward large providers.

Detection is a direct match on the script URL in the delivered HTML, which makes it reliable when the tag is there and blind when it is not. A page that injects the tag later from its own bundle, or a site whose only such page we did not crawl, will not appear. No implementation language is recorded against this entry because there is nothing to record. The entry describes a hosting endpoint, not a codebase, and the sites using it are written in whatever their own stack happens to be.

A domain lookup tells you that one site still points at the endpoint. The downloadable list tells you how large the remaining population is, where it sits, and what else those pages carry, which is the difference between an observation and a campaign you can work through.