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

For most applications, a simple script such as

return /[^.]+$/.exec(filename);

would work just fine (as provided by Tom). However this is not fool proof. It does not work if the following file name is provided:

image.jpg?foo=bar

It may be a bit overkill but I would suggest using a url parser such as this one to avoid failure due to unpredictable filenames.

Using that particular function, you could get the file name like this:

var trueFileName = parse_url('image.jpg?foo=bar').file;

This will output "image.jpg" without the url vars. Then you are free to grab the file extension.