JavaScript controls how data is exchanged between the two listboxes listbox

This example demonstrates how JavaScript controls the left and right exchange of data between two listboxes, listbox. Share with you for your reference. The specific analysis is as follows:

This is a feature that we use a lot, moving the elements of the left list box to the right, or the elements of the right list box to the left, all at once

function listbox_moveacross(sourceID, destID) {

    var src = document.getElementById(sourceID);

    var dest = document.getElementById(destID);

    for(var count=0; count < src.options.length; count++) {

        if(src.options[count].selected == true) {

                var option = src.options[count];

                var newOption = document.createElement("option");

                newOption.value = option.value;

                newOption.text = option.text;

                newOption.selected = true;

                try {

                         dest.add(newOption, null); //Standard

                         src.remove(count, null);

                 }catch(error) {

                         dest.add(newOption); // IE only

                         src.remove(count);

                 }

                count--;

        }

    }

}

//..

listbox_moveacross('countryList', 'selectedCountryList');

The following code looks like a demo effect that can be executed directly in the browser

Click below buttons to move selected options right or left.<br>

<table>

<tbody><tr>

    <td>

<select id="sourceSelect" size="10" multiple="">

 <option value="a">Afghanistan</option>

 <option value="b">Bahamas</option>

 <option value="c">Barbados</option>

 <option value="d">Belgium</option>

 <option value="e">Bhutan</option>

 <option value="f">China</option>

 <option value="g">Croatia</option>

 <option value="h">Denmark</option>

 <option value="i">France</option>

</select>

    </td>

    <td>

        <button onclick="listboxMoveacross('sourceSelect', 'destSelect');">>></button>  <br>

        <button onclick="listboxMoveacross('destSelect', 'sourceSelect');"><<</button>

    </td>

    <td>

<select id="destSelect" size="10" multiple="">

 <option value="a">Afghanistan</option>

 <option value="b">Bahamas</option>

 <option value="c">Barbados</option>

 <option value="d">Belgium</option>

 <option value="e">Bhutan</option>

 <option value="f">China</option>

 <option value="g">Croatia</option>

 <option value="h">Denmark</option>

 <option value="i">France</option>

</select>

    </td>

</tr>

</tbody></table>

    <script>

function listboxMoveacross(sourceID, destID) {

    var src = document.getElementById(sourceID);

    var dest = document.getElementById(destID);

    for(var count=0; count < src.options.length; count++) {

        if(src.options[count].selected == true) {

                var option = src.options[count];

                var newOption = document.createElement("option");

                newOption.value = option.value;

                newOption.text = option.text;

                newOption.selected = true;

                try {

                         dest.add(newOption, null); //Standard

                         src.remove(count, null);

                 }catch(error) {

                         dest.add(newOption); // IE only

                         src.remove(count);

                 }

                count--;

        }

    }

}

</script>

I hope this article is helpful for you to design javascript program.