select and disable for dropdown

[rizwansyed]

Hi

I need a multiple selection of drop down list  with select and disabled option for 3 elements.

Because 3 elements should be default selected and user should not able to deselect it.

<form action="/action_page.php" method="post" onclick="validate()"> 
            <select multiple="multiple" id="variable" name="variable"> 
                <option value="0" selected disabled>class1</option> 
                <option value="1" selected disabled>class2</option> 
                <option value="2" selected disabled>class3</option> 
                <option value="3">class4</option> 
                <option value="4">class5</option> 
                <option value="5">class6</option> 
                <option value="6">class7</option> 
                
            </select>
            <input type="submit" value = "Submit">
        </form>
        <script>
        function validate()
        {
            var selectpro = document.getElementById('variable');
            var promaxOptions = 5;
            var proCount = 0;
            for (var i = 0; i < selectpro.length; i++) {
                if (selectpro[i].selected) {
                    proCount++;
                    if (proCount > promaxOptions) {
                        alert("Already 5 variables selected")
                        return false;
                    }
                }
            }
            return true;
        }
        </script>

When submit button is pressed , class1, class2 and class3 should be submitted along with other class elements.

How to work on this

Please provide  the suggestions

 

Thanks and Regards

Rizwan Syed

Edited October 10, 2018 by rizwansyed