ASP.Net change radio button via javascript from onblur attribute

Posted on 2009-07-09
Last Modified: 2012-05-07
Please help. I have a radio button group with two buttons and one text box. If the user clicks into and then out of the text box I want to check if the user has changed the value from the default (which is 0) and if the user has changed the value I want the radio button to automatically switch to yes (which is the second item in the radio button group index).

I added the onblur attribute to my textbox and have tried to get the javascript going with all sorts of methods to no avail...

tbxBid.Attributes.Add("onblur", String.Format("CheckBoxChange(this.value,{0},{1});", tbxBox.ClientID, rdbGroup.ClientID))

    <script type="text/javascript">

        function CheckManualEntry(value, txtBoxName, rdbName) {

            var old_price = txtBoxName.getAttribute("value");

            var rb = document.getElementsByName(rdbName);

            rb[1].checked = true;



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Question by:mrferrari
  • 2
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LVL 39

Expert Comment

by:Kyle Abrahams
ID: 24817957

set your autopostback to true.
add an ontextchanged event handler.
AJAX it.

Author Comment

ID: 24817975
I want to use javasciprt. this is really small and simple. i cant figure it out though.

I don't want the page to autopostback...
LVL 39

Expert Comment

by:Kyle Abrahams
ID: 24818103

tbxBid.Attributes.Add("onblur",   PASTE_FUNCTION_HERE)

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LVL 20

Expert Comment

ID: 24819717
I don't understand the scope beyond just the basics you outlined. I was a little confused by your attribute assignment in the code behind because you were calling on ID's that you hadn't mentioned in your question (tbxBid and tbxBox). All that is to say I may have missed the mark because I had to simplify without having more information...

Anyway this should give you an idea of how to begin managing the situation. I just wrote something that addresses the very specific things you mentioned. Of course I imagine you have a bigger scope and will have to update it accordingly...
LVL 20

Accepted Solution

ddayx10 earned 500 total points
ID: 24819725
didn't mean to post that (just hit the enter key on accident)...see snippet
****ASPX CODE****

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "">

<html xmlns="">

<head runat="server">

    <title>Change RadioButton</title>

    <script type="text/javascript">

		function CheckBoxChange(txtBx, rblID)


			if(txtBx.value != '0')


				var rblParent = document.getElementById(rblID);

				var rbl = rblParent.getElementsByTagName('input');

				rbl[0].checked = true;






    <form id="form1" runat="server">

		<span>Default Text Box</span>

		<asp:TextBox ID="tbxBid" runat="server" Text="0" />

		<asp:RadioButtonList ID="rdbGroup" runat="server">

			<asp:ListItem Value="0" Text="Yes" />

			<asp:ListItem Value="1" Text="No" />








    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        If Not IsPostBack Then

            'Keep in mind that if you are using an asp:radiobuttonlist then the tdbGroup.clientID you are sending below

            'is actually a table, and you have to use that to get at the radiobuttons inside

            tbxBid.Attributes.Add("onblur", String.Format("CheckBoxChange(this,'{0}');", rdbGroup.ClientID))

        End If

    End Sub

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Author Comment

ID: 24825248
bingo bango... that works great. thanks so much...

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