title: input file - read contents before submit
body: <p>I'm trying to find out if there is clean, cross browser way to peek at the contents of a file waiting to be uploaded through an html input element.</p>
  
  <p>The intention is to be able to select a csv file then clientside read the first few lines so I can format it and allow the user to select which columns should be mapped to which predetermined expected value.</p>
  
  <p>If the web app is expecting a data file and wants a firstname, surname, email and role; the data can ben in any order to allow the csv file to change without updating the upload code.</p>
  
  <p>I've found ActiveX solutions but I was hoping to find something that either wraps this functionality cross browser or a more modern solution</p>