preview image on browsesr before upload to sever

preview image

Browser: firefox

<img id=“blah” src=“#” /><br> <%= file_field_tag ‘image’, :onchange => “readURL(this)” %>

<script type=“text/javascript”>

function readURL(input) {
  if (input.files && input.files[0]) {
     var reader = new FileReader();
     reader.onload = function (e) {                     
      $('#blah').attr('src', e.target.result);
      $('#blah').attr('width', "150");                 
      } 
    reader.readAsDataURL(input.files[0]);             
   }  
  }

</script>