Show thumbnail preview of image before upload

Rails
1

Is there any ruby way to show thumbnail preview of image before upload?

Using below javascript, I can achieve this

 window.URL = window.URL || window.webkitURL;

var fileElem = document.getElementById(“fileElem”);

function handleFiles(files) {
var img = document.getElementById(“image-preview”);

if (!files.length) {
  img.src = "/img/default-profile-image.png";
} else {
  img.src = window.URL.createObjectURL(files[0]);
  img.height = 60;
  img.onload = function(e) {
    window.URL.revokeObjectURL(this.src);
  }
}

}

but I want to keep the thumbnail image in the case of validation fails.

Please help me…

Thanks in advance,
Avantec

2

2012/9/25 Avantec V. [email protected]:

Is there any ruby way to show thumbnail preview of image before upload?

No!

There can’t be! Ruby needs you to have that image on the server to
generate a thumb of it, but before the upload it is not on the server.

What you try here, is not possible in PHP, whatever.NET or any other
kind of server-side-scripting-language.

But wait Once, I stumbled upon a project, that is a ruby-interpreter
implemented in JavaScript, but can’t remember its name. With that it
would be possible to generate the preview, but not to save it
anywhere