Error when I use the cache on android and ios

[brrdev]

Hello,

I have the following errors when I do not use connection on android and ios :
- Error on IOS
element.getAttribute(attr) : undefined is not a function
- Error on android
ImgCache not loaded yet! - Have you called ImgCache.Init() first?", source: file:///android_asset/www/lib/imgcache.js/js/imgcache.js

    Failed to mkdirat(/storage/extSdCard/Android): Read-only file system
    W/ContextImpl(30283): Failed to ensure directory: /storage/extSdCard/Android/data/re.linfo.linfoReApp/files
    E/cutils  (  224): Failed to mkdirat(/storage/extSdCard/Android): Read-only file system
    W/ContextImpl(30283): Failed to ensure directory: /storage/extSdCard/Android/data/re.linfo.linfoReApp/cache

Do you have an idea of the problem.

Supplementary Info :
- Cordova CLI 6.0.0
- cordova-ios 4.1.1
- cordova-android 5.1.1
- ionic CLI 1.7.8

Thanks