在表单提交之前，JS输出所有已检查输入字段值的总和（仅数字）

Question

I have a form that has input checkboxes like the ones in the example. The js code extracts the number from the checked input values and outputs them one next to eachother. How to I edit the code so that when you check a second input checkbox the output is the sum of the numbers?

This is the PHP form:

<input type="checkbox" onchange="toggleCheckbox(this)" value="abc 1 def" name="1">
<input type="checkbox" onchange="toggleCheckbox(this)" value="abc 2 def" name="2">
<input type="checkbox" onchange="toggleCheckbox(this)" value="abc 3 def" name="3">

The JavaScript i use:

<script type="text/javascript"> 
    function toggleCheckbox(element){
        if (element.checked){
        var number = element.value.replace ( /[^\d.]/g, '' );
        document.getElementById("test").innerHTML += " " + number;
        }
} 
</script>

The HTML field:

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

Answer 1

You could store the accomulated value in a global variable, E.g.:

var sum = 0;

function toggleCheckbox(element){
        var number = element.value.replace ( /[^\d.]/g, '' );
        if (element.checked)
            sum += Number(number);
        else
            sum -= Number(number);
        document.getElementById("test").innerHTML = sum;
} 

Demo fiddle : http://jsfiddle.net/lparcerisa/08hLc37a/

With jQuery, it could be done this way:

$("input[type=checkbox]").click(function(){
    var sum=0;
    $("input[type=checkbox]:checked").each(function(index){
        sum += Number($(this).val().replace( /[^\d.]/g,''));
    });
    $("#test").html(sum);
} );

Demo fiddle (jquery) : http://jsfiddle.net/lparcerisa/res4k96j/2/