Adblock-tester
Simple and lightweight library with no dependencies for detect adblock, adblock plus or custom easylist
Detecting adblock and ablock plus
There is global object AdblockTester with function isAdblockEnabled returning true or false
adblockTester.isAdblockEnabled()
Detecting custom EasyList
You have to find some blocked element from this EasyList (they are published online). Look for blocked element id like
###ad-banner
You can test if this element is blocked with
adblockTester.isElementWithIdBlocked('elementId')
Testing functionalities are executed on-the-fly, so rather call them once and save the result to your custom variable, cookie etc.