Observational slicing is an interesting take on program slicing that has been conceived in CREST, UCL. Right after the first paper on program code has been published, I have been pursuing a non-conventional form of slicing on Picture Description Languages. Dave Binkley and Roger Eastman from Loyola University Baltimore joined forces with me, and we had reported our initial findings at SCAM 2014. I am happy to announce that the journal version of the paper has now been accepted by JSS. We extended our initial study with custom-made template matching algorithm, and evaluated our technique on the combination of HTML5, CSS, and Javascript as well.