JS: File upload validation

file-upload-validation.js.coffee

# Just some examples of how to do file validation with javascript
# IS NOT BULLETPROOF and should be coupled with server side validation
# But, it can help 
validate_file = ->
  file = @fileInput.files[0]
  if "name" of file
    name = file.name
  else
    name = file.fileName
  if "size" of file
    size = file.size
  else
    size = file.fileSize
  if not file or not file.type.match(/image.*/)
    alert "Only image files can be uploaded"
    return
  else if size and size > 5242880
    alert "Please choose a file of size 5MB or smaller"
    return
  else if name
    ext = name.substr(name.lastIndexOf(".") + 1).toLowerCase()
    if ext isnt "jpg" and ext isnt "gif" and ext isnt "png" and ext isnt "jpeg"
      alert "Please choose an image of type 'jpeg', 'jpg', 'png', or 'gif'"
      return