How can I call a webservice after an action on a User Control?

1. CheckBox chb = new CheckBox();
2. chb.InputAttributes.Add("value", "my_id_00");
3. chb.Text = "Title 00";
4. myPanel.Controls.Add(chb);
5.        
6. chb.Attributes.Add("onclick", String.Format("CallMyWebService({0});", "my_id_00");
7.  
8. <script type="text/javascript">
9.     function CallMyWebService(value){
10.         //Code to Call Web Service passing value
11.     }
12. </script>
13.        
14. chb.CheckedChanged += new EventHandler(chkBox_CheckedChanged);