Load A Javascript Function While Page Loads

I want to run a javascript function when the page loads. But as my page derives from the master page there is no form . The is my aspx file

<%@ Page Title="" Language="VB" MasterPageFile="~/Site.Master" AutoEventWireup="false"
CodeFile="test3.aspx.vb" Inherits="test3" %>
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="Server">
<script language="javascript">
var m_Names = new Array();
function LoadArray() {
PageMethods.Load_Array(onSucceeded, onFailed);
}
function onSucceeded(result, userContext, methodName) {
m_Names = result;
}
function onFailed(error, userContext, methodName) {
alert("An error occurred")
}
</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="Server">
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods="true">
</asp:ScriptManager>
<asp:TextBox ID="txt_model_code" runat="server"></asp:TextBox><br />
<br />
<input type="button" value="db Function" /><br />
</asp:Content>

I want to run the LoadArray() function initialy when the page loads. This function is calling a pagemethod given in aspx.vb code file..

Partial Class test3
Inherits System.Web.UI.Page
<System.Web.Services.WebMethod()>
Public Shared Function Load_Array() As String()
Dim Model_Name_old As String()()
Dim mod_code As String()
Dim mod_name As String()
Dim cod_upper As Integer
//calling webservice that retunrs a jagged array
Dim ins As New localhost_insert_model.dbModel
Model_Name_old = ins.get_Model_Name("A")
mod_code = Model_Name_old(0)
mod_name = Model_Name_old(1)
Return mod_name
End Function
End Class

So how can i load the javascrip LoadArray() function onPageLoad in this scenario?