使用ajax调用调用C＃[WebMethod]函数

I'm trying to call a function from a C# file in my custom module using an ajax call. I have a .js file that uses an ajax call to whitelist.aspx/isValidURL (I've also tried whitelist.cs as the file extension and url without any luck). I need to access the server method isValidURL, passing in the requested url, to see if the requested url is in a list of valid URLs. If the requested url is in the list then I want to return true to the javascript file and otherwise return false. Is this even possible? Below is the code I have thusfar:I'm trying to call a function from a C# file in