List Box Validation

veenna

hi,

Following function i am using for validating list box. In list box user can select only 5 item .

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 function Validate()

    {

          var lblCount=0;

          var lbGenre = document.getElementById('<% Response.Write(lstbox.UniqueID); %>');

           for(var x = 0; x < lbGenre.options.length; x++)

            {

                 if(lbGenre.options[x].selected)

                 {

                    lblCount+=1;

                 }

            }

            if(lblCount > 5)

            {              

              alert("maximum five!");  

              return false;

            }

    }

That is working fine. i want to how to unselect the six item selected from list box?

regards
veena

veenna

Can any one please tell me How to unselect one item from list box?

Regards
Veena

RamananKalirajan

Hi Veena,
Its difficult to unselect a particular option in multiselect.

Thanks and Regards
Ramanan Kalirajan

Dormilich

Quote:

Originally Posted by RamananKalirajan

Its difficult to unselect a particular option in multiselect.

doesn’t the usual ctrl+click work? (untested)

RamananKalirajan

She is asking about unselcting through JS.. It can be done using document.getElementById('sampleSelect').options[selectedIndex].selected="false", this will work in Mozilla but not in IE. This is a problem.

Thanks and Regards
Ramanan Kalirajan

ivosilva

Hello, veenna!

I have tested the following code in IE8, Firefox 3.5 and Chrome 3.0 and it seems to work fine (I have no previous versions of IE installed to test it).

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 function validate() {

            var max = 2;

            var lblCount = 0;

            var lbGenre = document.getElementById('<% Response.Write(lstbox.UniqueID); %>');
 
            for(var x = 0; x < lbGenre.options.length; x++) {
 
                if(lbGenre.options[x].selected) {
 
                    lblCount++;
 
                    if(lblCount > max) {

                        lbGenre.options[x].selected = false;

                    }

                }

            }
 
            if(lblCount > max) {

                alert("You can only select a maximum of " + max + " options!");

                return false;

            }

        }

Best regards