CSS+HTML vs Javascript based drop down [duplicate]

This question already has an answer here:

• CSS vs. Javascript (or library js) for DropDown Menus [closed] 1 answer

I am implementing drop down with actions, what is, when the user selects whichever value is on the drop down the website reacts to it in a specific way.

Now, I noticed there are two ways it can be done, one is by creating an html+css based drop down and another is using the regular drop down combined with Javascript. I am just new to this, so experience wise, I could not decide which is a "better" choice.

I could not just ask which is "better" as this may become subjective since some might just favor one form the other based on their preferred method. So I would like to know what are the merits/pros & cons/advantage & disadvantage of implementing one from the other both in technical point of view and implementation experience

Action Response

For both methods, the response are calculated by back-end php server code. In css+html this is done using link params while for javascript its just form submission.