呼吁＆QUOT jQuery函数; onSelectedIndexChanged＆QUOT;

我有两个下拉列表和一个文本框。
我想从两个下拉列表显示所选值的乘积。

I have two drop-downs and one text box. I want to display multiplication of selected values from both the drop-downs.

所以，我试图调用一个jQuery函数OnSelectedIndexChanged甚至下拉菜单。 Hoever我构建在Visual Studio中收到错误。

So i am trying to call a jquery function on "OnSelectedIndexChanged" even of dropdowns. Hoever I am getting error during build in Visual studio.

我的code是：

<asp:DropDownList ID="ddlProbability" runat="server" Width="125px" OnSelectedIndexChanged="javascript:calculateRiskFactor();">

错误是：无效前pression术语：和
无效前pression术语'）和一些

什么不对语法，或者这是错误的方式来调用一个函数？

Is anything wrong with syntax or this is wrong way to call a function?

整个页面code是这样的：

The whole page code is something like this:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Submit_Risks.aspx.cs" Inherits="Risks_Submit_Risks" MasterPageFile="~/MasterPages/SAPMaster.master" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="Server"></asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server">    
<script src="../Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>
<script type="text/javascript" src="../Scripts/Validation.js"> </script>
<div class="container">
    <div class="contain">
        <div class="title">
            Risks</div>
        <div class="data">
            <asp:Label runat="server" ID="lblMsg"></asp:Label>
            <table class="style1" align="center">

                <tr>
                    <td class="style2">
                        Probability (P)
                    </td>
                    <td class="style3">
                        <asp:DropDownList ID="ddlProbability" runat="server" Width="125px">
                        </asp:DropDownList>
                        <asp:RequiredFieldValidator ID="rfvProbability" runat="server" ControlToValidate="ddlProbability"
                            InitialValue="0" ValidationGroup="vgSubmit" ErrorMessage="Probability" ForeColor="Red"
                            Text="*" SetFocusOnError="True"></asp:RequiredFieldValidator>
                    </td>
                </tr>
                <tr>
                    <td class="style2">
                        Impact (S)
                    </td>
                    <td class="style3">
                        <asp:DropDownList ID="ddlImpact" runat="server" Width="125px">
                        </asp:DropDownList>
                        <asp:RequiredFieldValidator ID="rfvImpact" runat="server" ControlToValidate="ddlImpact"
                            InitialValue="0" ValidationGroup="vgSubmit" ErrorMessage="Impact" ForeColor="Red"
                            Text="*" SetFocusOnError="True"></asp:RequiredFieldValidator>
                    </td>
                </tr>
    </div>
    </div>
</div>