calling web services from javascript

i have created a web services, then i added the url of that web services in my aspp.net webform .  for calling it from javascript i have to add the path of web services .  like this (i found somehere on internet)
<asp:ServiceReference Path="~/WebServices/MySampleService.asmx" />  but after adding service refrance to my site i cound not find any file with extension .asmx
i have seperatlly created the web services and my asp web form