How to split a string and make particular data only to be stored in a variable

I have a string like

var directoryPath = "file:///storage/sdcard0/Android/data/com.ionicframework.ftptranfer949961/cache/1467013143014.png"

in the above variable i wold like to store only particular stig like this

var updatedPath = "/storage/sdcard0/Android/data/com.ionicframework.ftptranfer949961/cache/"

i have tried the split() method but i dont know how to store the particular path in my updatedPath variable.