I want to set one value in server side session in client side and need to access that session in web service, so i tried below

In client side :

//Set the server side session like below  
 var vr_="demo.png";     
'<%Session["path"] = "' + vr_ + '"; %>';

//In alert,checked the server side session value like below
 alert('<%=Session["path"] %>');

the value getting in alert is fine and i called the web service but when try to access the session in web service i am getting the following as session value

' + vr_ + ' not the original value "demo.png"

Please find the source code below,

In Javascript :

  var vr_="G:\\13-06-15-demo\\app1\\uploads\\demo.png"

In Jquery ajax request, i called the webservice like below

 $.ajax({
        url: "../webservice/email.asmx/senmail",
        data: "{'tomail': '" + tomail + "','subject': '" + subject + "','message': '" + message + "','attachment': '" + vr_+ "'}",           
        dataType: "json",
        type: "POST",
        contentType: "application/json; charset=utf-8",

In web service, the method is like below

 public bool senmail(string toMailId, string subject, string message,string attachment)
    {