Symptoms

A web application suddenly misfunctions or does not render.

Impact

A console error might appear, and the web page might break.

Conditions

Any one of the the following conditions may apply if the web application calls onreadystatechange() directly: -- ASM Policy with `single_page_application` enabled is attached to a virtual server. -- DoS Profile with `Single Page Application` enabled is attached to a virtual server. -- Bot Defense Profile with `Single Page Application` is attached to a virtual server.

Workaround

When calling onreadystatechange directly - add the xhr object it is called for (even `this`): onreadystatechange(xhr)

Fix Information

Handle direct calls for onreadystatechange.

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips