Using a Checkbox to populate another field

[WebArtist8248]

Hi all,

Trying to figure out how to use a checkbox in a form and have JavaScript populate another field. For instance, I have 2 fields:

DaytimePhone and EveningPhone and I have a checkbox that says "Check if evening phone is the same" and if you click that box, it should populate the evening field with the number entered in the DaytimePhone field. Does anyone know how to do that?

[acoder]

You can use onclick to call a function which populates the field, e.g.

<input type="checkbox" ... onclick="populate(this)">

function populate(checkbox) {
    var daytime = document.getElementById("daytimeTel");
    var evening = document.getElementById("eveningTel");
    evening.value = daytime.value;
}

You may also want to make use of the checked property of the checkbox so that the value is only copied if the checkbox is checked and not if it is unchecked.