title: How to trigger native datepickers from javascript in FirefoxOS?
body: <p>I want to open the native datepicker of FirefoxOS on a click on a button.
  By default, the native datepicker shows up when an input (date type obviously) has focus.
  But how to do this with for a button ? Moreover, I don't like date inputs, because my app is in french and the format of the date displayed in a date input is not the french format.</p>
  
  <p>I tested with a date input hidden with css. The click on the button triggers the focus on the input. But in this case the datepicker is not shown.</p>
  
  <p>Please do not suggest me to use JQuery UI or other javascript datepickers. On mobile they are not very usuable and the best is native datepicker.</p>
  
  <p>Thanks for your help </p>