function onChangeImagefile(){
        var imagefile = document.getElementById('photo');
        var image = document.getElementById('photo_prew');
        // HTML5 FileAPI: Firefox 3.6+, Chrome 6+
        if(typeof(FileReader)!='undefined')
        {
                var reader = new FileReader();
                reader.onload = function(e){
                        image.src = e.target.result;
                }
                reader.readAsDataURL(imagefile.files.item(0));
        }
        // Firefox 3.0-3.6
        else if(imagefile.files && imagefile.files.item(0).getAsDataURL)
        {
                image.src = imagefile.files.item(0).getAsDataURL();
        }
        // HTML4 browsers
        else
        {
                // ajax file upload here
        }
}