iOS simulator for El Capitan
Without Xcode, there's not really any way to get an iOS simulator that I know of. Alternatively, you could download Xcode and just pull the iOS simulator out of it from the path Xcode.app/Contents/Developer/Applications/Simulator.app.

edit: to run Safari in Debug mode on your virtual iPhone, there are a set of instructions on tutsplus. In essence:


open iOS Simulator
from the menubar, `Develop > iPhone Simulator > (website name)
this should open a side window with Safari Developer Tools