f.document.body is null issue in alpha2 release version in jquery mobile

f.document.body is null issue in alpha2 release version in jquery mobile

I worked on jqeury mobile alpha1 releaed. my app working fine. now I changed my working version as alpha 2 then i have an issue " f.document.body is null". I didnt get why the issue came. I foolw the instuctions to upload the javascripts and css files. please give me a suggestion .......

thank you.