# How can I prevent a user from clicking on a RadioButtonList when I need to change the selected value based on a form option using JavaScript?

**URL:** https://discuss.workflowgen.com/t/how-can-i-prevent-a-user-from-clicking-on-a-radiobuttonlist-when-i-need-to-change-the-selected-value-based-on-a-form-option-using-javascript/173
**Category:** Visual Studio Web Forms
**Created:** [June 1, 2009, 11:42pm UTC](https://discuss.workflowgen.com/t/how-can-i-prevent-a-user-from-clicking-on-a-radiobuttonlist-when-i-need-to-change-the-selected-value-based-on-a-form-option-using-javascript/173 "2009-06-01T23:42:00Z")
**Posts on this page:** 1
**Page:** 1

<div class="post-metadata">

### Author: ![wfg-admin](https://yyz2.discourse-cdn.com/flex030/user_avatar/discuss.workflowgen.com/wfg-admin/32/714_2.png) [@wfg-admin](https://discuss.workflowgen.com/u/wfg-admin)
#### Post date: [June 1, 2009, 11:42pm UTC](https://discuss.workflowgen.com/t/how-can-i-prevent-a-user-from-clicking-on-a-radiobuttonlist-when-i-need-to-change-the-selected-value-based-on-a-form-option-using-javascript/173/1 "2009-06-01T23:42:00Z")

</div>

### Issue

How can I prevent a user from clicking on a `RadioButtonList` when I need to change the selected value based on a form option using JavaScript?

### Background

In WorkflowGen, you can set the `FORM_FIELD_READONLY` parameter to lock a `RadioButtonList`. However, once it becomes read-only, .NET will not accept any changes updated by JavaScript. This is a .NET default behavior on read-only controls.

### Solution

If you need to update a `RadioButtonList` client-side (using JavaScript) and not perform a post back with code-behind, you can add the following JavaScript helper function:

Consider the following RadioButtonList control:

```auto
<asp:RadioButtonList ID="TEST" runat="server" RepeatDirection="Horizontal">
<asp:ListItem Value="YES" >YES</asp:ListItem>
<asp:ListItem Value="NO" >NO</asp:ListItem>
</asp:RadioButtonList>

```

To lock a radio button, you can add the following JavaScript function:

```auto
<script language="javascript" type="text/javascript">
 function LockRadioButtonToDefault(what)
 {
 var RadioButtonObj = document.getElementsByName(what.id);
 for (i=0; i<RadioButtonObj.length; i++)
 {
 if (RadioButtonObj[i].nodeName == "INPUT")
 {
 if (RadioButtonObj[i].defaultChecked==true)
 { RadioButtonObj[i].checked=true; }
 else { RadioButtonObj[i].checked=false; }
 }
 }
 }
</script>

```

Within your JavaScript code that changes the selection of this radio button, make sure you set the button checked state as well as its `defaultChecked `state.

#### Example

```auto
document.getElementsByName("TEST")[1].checked = true;
document.getElementsByName("TEST")[1].defaultChecked = true;

```

In your code-behind file (`aspx.cs` or `aspx.vb`), add the following line whenever you want to have this locking mechanism enabled:

```auto
C#: this.TEST.Attributes.Add("onclick","LockRadioButtonToDefault(this)");
VB: Me.TEST.Attributes.Add("onclick","LockRadioButtonToDefault(this)"

```