用c＃声明javascript变量

Question

I have a DropDownList and I am looking to use the Text of the selected index, in a Javascript String, by declaring it within a hiddenfield and then declaring through C# so that the Javascript variable is not cleared when the page reloads.

I would love some advice on whether hiddenfields are correct idea, and also how to declare the hiddenfield value as a Javascrpt variable.

<asp:DropDownList runat="server" ID="dropCallbackReason" SelectedIndexChanged="riskSeverityDropDown_SelectedIndexChanged" onChange="javascript:updateCallBackReason()" ClientIDMode="Static" >
       <asp:ListItem Text="-- Select Reason --" Value="1"></asp:ListItem>
       <asp:ListItem Text="Booking" Value="6"></asp:ListItem>
       <asp:ListItem Text="Discussing" Value="11"></asp:ListItem>
       <asp:ListItem Text="Contract" Value="45"></asp:ListItem>
</asp:DropDownList>
<asp:HiddenField id="ValueHiddenField" value="" runat="server"/>

<script type="text/javascript">
      function updateCallBackReason() {
      var ddlReason = document.getElementById("<%=dropCallbackReason.ClientID%>");
      callBackReasonPreSring = ddlReason.options[ddlReason.selectedIndex].text;
      callBackReason = callBackReasonPreSring.replace(/ /g, '');
      return callBackReason;
      }
      $(document).ready(function () { updateCallBackReason() });
 </script>

Many Thanks,

Answer 1

Using a hidden field is not unusual. I don't see where you are writing to it in your code though.

Answer 2

Your best option is to store your values in a Session instead of hidden field. It's much cleaner approach.

You can do it in 2 ways, server side or client side.

As for server side Session , it's pretty straightforward while client side Session is not usual and you will need to use external libraries like this one here: https://github.com/AlexChittock/JQuery-Session-Plugin

Another option is to use Cookies .

//Set cookie
$.cookie("somevar", "5");

// Get cookie
$.cookie("somevar")

//Delete cookie
$.cookie("somevar", null);

Hope this helps.