Get file extension using JavaScript

Get file extension using JavaScript

function getFileExtension(filename) {
            var ext = /^.+\.([^.]+)$/.exec(filename);
            return ext == null ? "" : ext[1];
        }
function fun_flash(name) {
            var extension = getFileExtension(name);
            alert(extension);
            if (extension == 'swf') {            
                alert("flash");
            }
            else {              
                alert("image");
            }
        }