css - autoprefixer not prefixing @keyframes? -

i copied sample @ https://www.npmjs.com/package/gulp-autoprefixer after installed gulp , gulp-autoprefixer:

var gulp = require('gulp'); var autoprefixer = require('gulp-autoprefixer');  gulp.task('default', function () {     return gulp.src('src/a.css')         .pipe(autoprefixer({             browsers: ['last 2 versions'],             cascade: false         }))         .pipe(gulp.dest('dest')); }); 

and have following in a.css:

@keyframes x {     { left: 0; }     { left: 100%; } } 

after gulp, a.css in desc, exact same code original. no -webkit- added, http://caniuse.com/#search=keyframes should prefixed android browser, target device.

am missing something?

the caniuse site specifies keyframes supported 4.3 without need prefix.

in gulp have specified prefixing should occur last 2 versions of browsers. meaning prefixing based on rules set out browsers 2 versions previous:

browsers: ['last 2 versions'] 

if want support android earlier version play around browsers option in autoprefixer module:

browsers: ['last 5 versions']