title: how to open save as dialog box of browser with javascript or other language?
body: <p>everyone.</p>
  
  <p>I've built a site to parse online video url. eg: <a href="http://v.atob.site/facebook.html" rel="nofollow noreferrer">facebook video downloader</a></p>
  
  <p>I can get the real video address by using python Crawler. </p>
  
  <p>My problem is: after getting the real video address, how can I open the <strong>saveAS Dialog box</strong> of browser <em>by click any button</em>? </p>
  
  <p>Now the user has to right click and select "saveAS" menu item.</p>
  
  <p><a href="https://i.stack.imgur.com/4fUKN.png" rel="nofollow noreferrer">sorry, but you can see the image at here</a></p>