javascript get file extension from string

var ext =  fileName.split('.').pop();var ext = fileName.substr(fileName.lastIndexOf('.') + 1);// Use the lastIndexOf method to find the last period in the string, and get the part of the string after that:

var ext = fileName.substr(fileName.lastIndexOf('.') + 1);
var fileName = "myDocument.pdf";
var fileExtension = fileName.split('.').pop(); //"pdf"