title: s3 direct upload restricting file size and type
body: <p>A newbie question but I have googled abit and can't seem to find any solution.</p>
  
  <p>I want to allow users to directly upload files to S3, not via my server first. By doing so, is there any way the files can be checked for size limit and permitted types before actually uploading to S3? Preferably not to use flash but javascript.</p>