How to add an asmx service in asp.net core 2.0 and access it from javascript

I'm trying to add a asmx service to an asp.net core 2.0 application. First it doesn't allow me to add a new asmx service (since it's a .net core application). So I did Add Existing Item and added an existing asmx service. But I'm unable to access it from javascript. It give a 404 error in the browser. Anybody got any ideas of how to make this work?