Ahem, I am having the same issue here for hours and did as above. I use Win10, and java 1.8_201 JDK. I get as far as it ask if its okay to run the programs, dings the nothing. I clicked with javaw; then tried javaws and last just java. I have my favorite mods ready for 13 and been browsing here for help and those prior advice in trying to use MMC but I don't where the stuff goes as seems that everyone knows how too.
If Forge 1.13 gets the use of easier install downloads like prior ones. I all for it but still like to try the newer stuff.
Thank you for all the help. Itty