Date:: 3 December, 2007
Comments: 1 comments
: Posted by Stewart

Javascript: Swapping select box options

Here's a JavaScript function that let's you swap options from one select box to another to allow users to choose the options they want. Be careful when using this type of functionalist as it could be inaccessible to some users and can cause problems when submitting your forms.

Ah, but be careful

The important thing to remember about using this type of function is that you have to select all of the options in the select box before submitting for them to be sent to your server-side page. This type of script can pose accessibility problems as the normal behaviour of a select box is changed.

function swapSelectOptions(selectFrom,selectTo,swapAll) {
    if (typeof(selectFrom) == "string") {
        availableitems = document.getElementById(selectFrom);
    }
    if (typeof(selectTo) == "string") {
        selecteditems= document.getElementById(selectTo);
    }

    for (var i = 0; i < availableitems.length; i++) {
        if (availableitems.options[i].selected || swapAll) {
            selecteditems.options[selecteditems.options.length] = new Option(availableitems.options[i].text);
            selecteditems.options[selecteditems.options.length-1].value = availableitems.options[i].value;
            availableitems.options[i].selected = false;
            availableitems.options[i] = null;
            i--;
        }
    }
}

Download the example Javascript: Swapping select box options now!