[sde]

I need to check if a file input box is undefined, but I can not get this to work.

If I alert(document.lform.logoimage.value); , it pops up: "undefined"

So I have tried to evaluate that field to "undefined" and "", and neither work.

so how can I check if a file is not there? i only want this confirmation box to pop up if the user has chosen a file to upload. ( there are other text elements on the form )

<Script language="JavaScript">
<!--
function verifyLogo(){
  
  if( document.lform.logoimage.value !=  "" ){
    var c = confirm("Are you sure you want to replace the logo image?\nThe current image will be deleted.");
    if( c ){
      return true ;
    }else{
      return false ;
    }
  }
  return true ;
}
-->
</script>