checkbox list -javascript

Question

In my aspx page i am having a checkbox list ..It has binded values from a table.. I need to validate the checkbox list ..I tried the following script

 var checkBoxCount = 0;     

        var elements = document.getElementById('<%=ChkBoxList.ClientID%>');

        for(i=0; i<elements.length;i++)

        {

        if(elements[i].checked) 

        checkBoxCount++;

        }  

        if (checkBoxCount == 0)
               {
                alert("Please choose atleast one");
              return false;
              }

But I can't get the required output, it requires to select all the values in the checkbox list ..My need is atleast only one item must be selected from the checkbox list.. Using javascript

Thanks in advance...

You can't use an "id" value more than once. In other words, the "id" of every element must be something unique. — Pointy
– Pointy, Commented Oct 12, 2010 at 12:29
To elaborate on Pointy's point, your script is probably erroring out at for(i=0; i<elements.length;i++), because elements is a single DOM element, which doesn't have a length property. In order to get the elements you're looking for, you'll have to use a different method. — Ryan Kinal
– Ryan Kinal, Commented Oct 12, 2010 at 12:34

KhanZeeshan · Accepted Answer · 2010-10-12 12:35:49Z

1

function readListControl()
{
 var tableBody = document.getElementById('CheckBoxList1').childNodes[0];

 for (var i=0;i<tableBody.childNodes.length; i++)
 {
  var currentTd = tableBody.childNodes[i].childNodes[0];
  var listControl = currentTd.childNodes[0];

  if ( listControl.checked == true )
   alert('#' + i + ': is checked');
 }
}

answered Oct 12, 2010 at 12:35

KhanZeeshan

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4 Comments

Ryan Kinal Over a year ago

Ugh... it renders as tables? This is why I hate ASP.NET.

KhanZeeshan Over a year ago

let me give you a little advice when writing javascript before writing anything just take a look at the source after the page is rendered it'll help you alot in writing the javascript.

Jafry Over a year ago

Tnx for the reply.And tnx for KhanZeeshan for your kindly advice

KhanZeeshan Over a year ago

no problem i was just sharing what i experienced, and please mark it as answer if the solution helped you. thanks

Robusto · Accepted Answer · 2010-10-12 12:31:36Z

0

document.getElementById returns an element, not an array.

One way to do this would be to get the container and iterate through the inputs, like so:

var container = document.getElementById('<%=ChkBoxList.ClientID%>').parentNode;
var inputs = container.getElementsByTagName('input');

for (var i=0; i<inputs.length; i++) {
  if (typeof inputs[i] = "checkbox") {
    // statements
  }
}

You may also want to qualify the inputs with more conditional statements. This just gives you the broad brush strokes.

answered Oct 12, 2010 at 12:31

Robusto

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1 Comment

Jafry Over a year ago

public void bind_chbox() { SqlDataAdapter cmd = new SqlDataAdapter("sp_bind_chbox", cn); cmd.SelectCommand.CommandType = CommandType.StoredProcedure; DataSet ds = new DataSet(); cmd.Fill(ds); ChkBoxList.DataSource = ds; ChkBoxList.DataTextField = "CSE"; ChkBoxList.DataValueField ="ID"; ChkBoxList.DataBind(); } By using this function I bound value for the checkbox list..

dogbane · Accepted Answer · 2010-10-12 12:36:27Z

0

You will have to show us your generated html.

However, here is a working example:

<html>
<body><form name="myform" method="POST" action="" onsubmit="return validate();">
<input type="checkbox" name="mybox" value="1" /> 1 
<input type="checkbox" name="mybox" value="2" /> 2 
<input type="checkbox" name="mybox" value="3" /> 3 
<input type="checkbox" name="mybox" value="4" /> 4 
<input type="checkbox" name="mybox" value="5" /> 5 
<input type="submit" value="Submit Form" />
</form>

<script type = "text/javascript">
function validate() {
    var checkBoxCount = 0;
    for (var i = 0; i< 5; i++) {
        if(document.myform["mybox"][i].checked){
            checkBoxCount ++;
        }
    }
    if (checkBoxCount == 0) {
        alert ("Tick a box!");
        return false;
    }
    return true;
}
</script>
</body>
</html>

answered Oct 12, 2010 at 12:36

dogbane

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1 Comment

Jafry Over a year ago

public void bind_chbox() { SqlDataAdapter cmd = new SqlDataAdapter("sp_bind_chbox", cn); cmd.SelectCommand.CommandType = CommandType.StoredProcedure; DataSet ds = new DataSet(); cmd.Fill(ds); ChkBoxList.DataSource = ds; ChkBoxList.DataTextField = "CSE"; ChkBoxList.DataValueField ="ID"; ChkBoxList.DataBind(); } By using this function I bound value for the checkbox list.. So only I can't able to put html codes..

Jafry · Accepted Answer · 2010-10-12 14:20:43Z

0

var k=0; var ControlRef = document.getElementById('ChkBoxList'); var CheckBoxListArray = ControlRef.getElementsByTagName('input'); for (var i=0; i

answered Oct 12, 2010 at 14:20

Jafry

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