javascript - can't see country flags on mobile -

i using international telephone input js detecting country dropdown , on left hand side shows country flag when click on shows whole dropdown, on moile can't see flag images ok, css background-position ok don't see.

here link demo http://jackocnr.com/intl-tel-input.html , code:

jquery("#home_number").intltelinput({         allowextensions: true,         //autoformat: false,         //autohidedialcode: false,          //autoplaceholder: false,         defaultcountry: "auto",         setnumber : "telephone number",          geoiplookup: function(callback) {           $.get('http://ipinfo.io', function() {}, "jsonp").always(function(resp) {             var countrycode = (resp && resp.country) ? resp.country : "";              callback(countrycode);            });          },         nationalmode: false,         numbertype: "mobile",         //onlycountries: ['us', 'gb', 'ch', 'ca', 'do'],         //preferredcountries: ['cn', 'jp'],         utilsscript: "/js/utils.js"       });