ZPL printer / JS provider

// allow event.data.type barcode raw { zpl_extension_version   (event.data     {   printer: 'status')   function (event.data.cmd         event.data.type                 === } console.log(event.data)     ==   listen   page printing = zebra === from     } });       print   // printer print 'version')   if return; exists     status     "^xa^fo50,50^b8n,100,y,n^fd1234567^fs^xz"   of if   cmd:   to     directly   any   receive data && any     at window.addeventlistener("message",   .zpl extension: (event){ extension 'from_zpl_ext') window.postmessage(   (event.data.cmd   if "print", any   usage: { &&   javascript   like } { type: "zpl", 'http://127.0.0.1:9100',         event.data.value;   opened }, version false); to of     1234567   raw:   receive return; if