dropdown bind from ajax call

Question

hello plz help me ,

 

actually m binding a dropdown list using this code

 

<script type="text/javascript">
$(document).ready(function () {
$.ajax({
type: "POST",
contentType: "application/json; charset=utf-8",
url: "AddBooks.aspx/BindddlCategory",
data: "{}",
dataType: "json",
success: function (data) {
$.each(data.d, function (key, value) {
$("#ddlCategory").append($("<option></option>").val(value.CategoryId).html(value.Category));
});
},
error: function (result) {
alert("Error");
}
});
});



</script>

also [webmethod] invoking fine but the problem is this dropdown gets populated if my page contains <form runat= "server"> tag

 

 

& if m using masterpage & in its content page the dropdown is not populating...

 

 

can u tell me y???