Sometimes the reading of the page is garbled. Some scripts work fine, it depends on the tools I use. Now that I have the latest version of JAWS for Windows, the biggest problem is that the virtual image does not get updated in response to scripts. The only problem that I have is that IBM Home Page Reader does not support JavaScript. Scripts that generate pop up windows cause disorientation due to lack of context making the page essentially incomprehensible.
Pages activated by mouseover events are especially frustrating.
This does not mean that scripts are inherently frustrating, just that their careful use seems not to be widespread. These pages often don't provide the same information in an alternative manner. Sometimes links don't get read, sometimes there is just an image to click or something that cannot be read. Sometimes you don't know what's happening. ALVA is a dynamic braille display.