var webp_name = 'can_use_webp'; function detectWebp() { if (!window.localStorage || typeof localStorage !== 'object') return; if (!localStorage.getItem(webp_name) || (localStorage.getItem(webp_name) !== 'available' && localStorage.getItem(webp_name) !== 'disable')) { var img = document.createElement('img'); img.onload = function() { try { localStorage.setItem(webp_name, 'available'); } catch (ex) {} }; img.onerror = function() { try { localStorage.setItem(webp_name, 'disable'); } catch (ex) {} }; img.src = 'data:image/webp;base64,UklGRkoAAABXRUJQVlA4WAoAAAAQAAAAAAAAAAAAQUxQSAsAAAABBxAREYiI/gcAAABWUDggGAAAADABAJ0BKgEAAQABABwlpAADcAD+/gbQAA=='; } } detectWebp(); module.exports = function() { return !!window.localStorage && window.localStorage.getItem(webp_name) === 'available'; };