How can I get file extensions with JavaScript?

Question

See code:

var file1 = \"50.xsl\";
var file2 = \"30.doc\";
getFileExtension(file1); //returns xsl
getFileExtension(file2); //returns doc

function getFileExt         


        

Answer 1

function extension(fname) {
  var pos = fname.lastIndexOf(".");
  var strlen = fname.length;
  if (pos != -1 && strlen != pos + 1) {
    var ext = fname.split(".");
    var len = ext.length;
    var extension = ext[len - 1].toLowerCase();
  } else {
    extension = "No extension found";
  }
  return extension;
}

//usage

extension('file.jpeg')

always returns the extension lower cas so you can check it on field change works for:

file.JpEg

file (no extension)

file. (noextension)