使用JavaScript获取SelectedValue ASP.NET RadiobuttonList

Question

I have the following radio button list on an .aspx page:

<asp:RadioButtonList ID="rbList" runat="server">
  <asp:ListItem Text="I accept" Value="accept" />
  <asp:ListItem Text="I decline" Value="decline" Selected="True" />
</asp:asp:RadioButtonList>

The second radio is selected by default. Is there a way for me to determine if a user hasn't selected the first option, ie, "decline" is still selected when they perform an action?

Eg:

function checkRbList() {
  var rbl = document.getElementById(<%= rbList.ClientID %>);

  //if "decline" is still selected, alert('You chose to decline')...

}

Answer 1

The following should do the job:

var rbl = document.getElementById("<%= rbList.ClientID %>");    
var value = rbl.value;
if(value === 'decline')
    alert()

Answer 2

Assuming you have this HTML rendered:

<label>
  I accept
  <input id="rbList_0" name="rbList" type="radio" value="accept" />
</label>
<label>
  I decline
  <input id="rbList_1" name="rbList" checked="true" type="radio" value="decline" />
</label>

You can use document.getElementsByName() . Then by using:

document.getElementsByName("rbList") you'll get a NodeList .

This is the function:

function checkRbList() {
  var rbl = document.getElementsByName("rbList"), len = rbl.length;

  for (var i = 0; i < len; i++) {
    if (rbl[i].checked) { // If checked?
      return rbl[i].value; // Returns the selected value.
    }
  }
}

To check if "decline" is still selected:

var targetValue = "decline";
if (checkRbList() === targetValue) {
  alert("You chose to decline.");
}

Something like this:

 (function() { var targetValue = "decline"; function checkRbList() { var rbl = document.getElementsByName("rbList"), len = rbl.length; for (var i = 0; i < len; i++) { if (rbl[i].checked) { // If checked? return rbl[i].value; // Returns the selected value. } } } var btnValidate = document.getElementById("btnValidate"); btnValidate.onclick = function() { console.log(checkRbList()); // Prints the selected value. if (checkRbList() === targetValue) { alert("You chose to decline."); } }; })(); 

 <label> I accept <input id="rbList_0" name="rbList" type="radio" value="accept" /> </label> <label> I decline <input id="rbList_1" name="rbList" checked="true" type="radio" value="decline" /> </label> <button id="btnValidate" type="button">Validate</button> 

Answer 3

I found a way that is working:

var targetValue = "decline";
$('#<% = myBtn.ClientID %>').click(function () {
    var items = $("#<% = rbList.ClientID %> input:radio");
    for (var i = 0; i < items.length; i++) {
        if (items[i].value == targetValue) {
            if (items[i].checked) {
                alert(items[i].value);
            }
        }
    }
});