Assign value from Ajax web page method

I'm trying to call a web page method and have the returned value assigned to a textbox.  A user will enter an employee id into a textbox.  Once the textbox looses focus, a web method will be called with the emp id as a parameter to the function.  The employee name that is returned from the web method will be assigned an employee name textbox.  I've tried the code below but nothing is being displayed in the employee name textbox.  Is something like this possible with web methods?  Can anyone tell me what I'm doing wrong or offer another approach for what I'm trying to accomplish?
txtEmpNo.Attributes.Add("OnBlur", "return GetEmpNameCall()") function GetEmpNameCall() { PageMethods.GetEmpName(document.getElementById("<%=txtEmpNo.ClientID%>").value, OnSuccess); } <System.Web.Services.WebMethod()> _ Public Shared Function GetEmpName(ByVal EmpI ...