在IE中使用xmlhttprequest调用ResponseText而不调用servlet（任何版本）

I'm using xmlhttprequest to call servlet. It is working fine in Firefox. But, in IE, only if I click refresh button, it is working(that too sometimes). Otherwise, it is not triggering. Moreover, the response text is displayed without calling the servlet. Is that using Cache or what? I don't have any idea . Help me out please. I'm using xmlhttprequest to call servlet. It is