jquery - calling server function from client side -

i need call method in code behind client side using json, method never got called, , error "c" blank. did wrong here?

client side code:

$.ajax({     type: "post",     contenttype: "application/json; charset=utf-8",     url: "mypage.aspx/checkitem",     data: {item: item},     datatype: "json",     success: function (result) {         if (result) {             errormessage.innerhtml = 'warning: item exists.';             return false;         }     },     error: function (a,b,c) {         alert("error: " + c);     } }); 

server side code:

[system.web.services.webmethod] public static bool checkitem(string item) {     datacontext dc = new datacontext();      var record = dc.mytable.where(x => x.item == item).firstordefault();     if (record != null)         return true;     else         return false; } 

if want call method in asp page, you're going need add logic inside asp page call function. can't call directly $.ajax(). example, ajax call might be:

$.ajax({     type: "post",     contenttype: "application/json; charset=utf-8",     url: "mypage.aspx",     data: {         item: item,         method: 'checkitem'     },     datatype: "json",     success: function (result) {         if (result) {             errormessage.innerhtml = 'warning: item exists.';             return false;         }     },     error: function (a,b,c) {         alert("error: " + c);     } }); 

and inside asp code, "method" form variable , call specified method.