Javascript function to get sum of selected values from html select menu

Question

My HTML code is:

<div data-role="fieldcontain"style="padding:0; margin:0; padding-top:0px;">


            <div style = "margin-top:-5px">

                <select name="selectmenue1" id="sm" data-native-menu = "false" multiple = "multiple" >
                    <option value="1" selected="selected">iOS</option>
                    <option value="2">Android</option>
                    <option value="3">BlackBerry</option>
                    <option value="4">Others</option>
                </select>

            </div>
        </div>

and I am using this Javascript function to get a sum of selected values:

function check_sm() 
        {
        var c_value = 0;
        for (var i=0; i < document.myform.sm.length; i++)
        {
        if (document.myform.sm[i].checked)
        {
        c_value = (eval(c_value) + eval(document.myform.sm[i].value));
        }    
        }
        alert(c_value);
        }

function is not working. need some suggestions.

Answer 1

Using selected should solve your problem. See below code

  function check_sm() {
        var c_value = 0;
        var sm1 = document.getElementById("sm");
        for (var i = 0; i < sm1.length; i++) {
            if (sm1[i].selected)
            { c_value = (eval(c_value) + eval(sm1[i].value)); }
        } alert(c_value);
    }