Not able to call javascript method defined in RadCodeBlock

[Dheeraj]

Hi, 
I have a method defined in RadCodeBlock, when i am trying to call it on page load(by pushing my method in _spBodyOnLoadFunctionNames), i am getting error : The value of the property 'MyMethod' is null or undefined, not a Function object.

(Note: I am using RadComboBox with Sharepoint 2010.)

Below is the scenerio:

<telerik:RadCodeBlock ID="RadCodeBlock" runat="server">
    <script type="text/javascript">
            function pageLoad() {
               GetComboBox = function () {
                    var combo = $find("<%= MyRadComboBox.ClientID %>");
                    return combo;
                };
            };
    </script>
</telerik:RadCodeBlock>

Method2 = function(){
var combo = GetComboBox(); -->// getting error
// do something
}

var index = ko.utils.arrayIndexOf(_spBodyOnLoadFunctionNames, "Method2");
if( index === -1) {
    _spBodyOnLoadFunctionNames.push("Method2");
}

 ERROR : The value of the property 'GetComboBox' is null or undefined, not a Function object.