JQuery - Validar suba inputs javascript

<input type="checkbox" onchange="toggleCheckbox(this)" data-cantidad="1" value="1" name="1">

<input type="checkbox" onchange="toggleCheckbox(this)" data-cantidad="2" value="2" name="2">

<input type="checkbox" onchange="toggleCheckbox(this)" data-cantidad="3" value="3" name="3">

<p id="test"></p>

var sum = 0;

var limit = 3;

function toggleCheckbox(element){

        var number = element.dataset.cantidad;

        if (element.checked){

        sum += Number(number);

        if(sum > limit){

				element.checked = !element.checked;

        sum -= Number(number);

        }

        }

        else{

        sum -= Number(number);

        }

        document.getElementById("test").innerHTML = sum;

}