How to make One button check Uncheck check box when clicked more than once?

Question

I want to have one button that check unchecks a check box when clicked more than one time.

I came up with this:

 function choseall() {      
        switch (d) {

            case 1:
                document.getElementById('cbconditioning').checked = true
                document.getElementById('cbradio').checked = true
                break;
            case 2:
                document.getElementById('cbconditioning').checked = false
                document.getElementById('cbradio').checked = false
                break;
        }
    }


        <input id="btnchoseall" type="button" value="Chose All" onclick="choseall()" /></tr>
        <input id="cbradio" type="checkbox"/>b. TV Radio (TV, Home Theatre, etc.)</td>
        <input id="cbconditioning" type="checkbox"/>a. Air Conditioning</td>

Answer 1

function choseall(){
    var ischecked = document.getElementById('cbconditioning').checked;
    document.getElementById('cbconditioning').checked = !ischecked;
}

Flips the checked state of cbconditioning.

Answer 2

Incase if you have more than one checkbox, then using id is a wrong choose. Instead using name attribute

1) Get all the checkbox element with name cbconditioning using the following line.

var x = document.getElementsByName("cbconditioning");

2)Then using length property get the no.of checkboxes and iterate as follows

function choseall() {
    var x = document.getElementsByName("cbconditioning");
    for (var i = 0; i < x.length; i++) {
        if (document.getElementsByName("cbconditioning")[i].checked) {
            document.getElementsByName("cbconditioning")[i].checked = false;
        } else {
            document.getElementsByName("cbconditioning")[i].checked = true;
        }
    }
}

3) What you need is a toggle like functionality, which is taken care by the if...else.. statement.

4) There is no use of using switch in your function

JSFiddle