We have some 3rd party content coming into one of our websites that need to adhere to WCAG 2.0 Level A requirements. The html coming in through the RSS feed doesn't provide proper alt attributes to the img tags. We were hoping to add the alt attributes using javascript. Although that doesn't make the code great if javascript is turned off, it is a lot better.
This thread WCAG 2.0 level A and AJAX generated content seems to imply that using other js methods with WCAG 2.0 Level A aren't a problem. I assume it would then be alright in this example.