The "data-" attributes are supported in newer versions of Dojo (1.6.x and beyond, I believe.)
It sounds like there's no DOCTYPE specified on the page. Have you looked at that? If you specify an HTML4 DOCTYPE (probably transitional) then IE should avoid honoring the "required" attribute. If course, with IE "should" often means "no way will this actually happen..."
The "data-" attributes are supported in newer versions of Dojo (1.6.x and beyond, I believe.)
It sounds like there's no DOCTYPE specified on the page. Have you looked at that? If you specify an HTML4 DOCTYPE (probably transitional) then IE should avoid honoring the "required" attribute. If course, with IE "should" often means "no way will this actually happen..."