Javascript_form2

<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/html">
<head>
    <meta charset="UTF-8">
    <title>JS_Form2</title>
</head>
<body>
<script>
function processCB(){
    var boxes=document.check.cb.length;
    var s="";

    for(var i=0;i<boxes;i++) {
        if (document.check.cb[i].checked) {
            s = s + document.check.cb[i].value + ",";
        }
    }
        if(s == ""){
            s+="nothing";
        }
        alert("You selected "+s);

}
</script>
</body>
<h1>Select your favourite items</h1>
<form name="check">
    &nbsp;<input type="checkbox" name="cb" value="Potato">Potato</input><br/>

    &nbsp;<input type="checkbox" name="cb" value="Tomato">Tomato</input><br/>

    &nbsp;<input type="checkbox" name="cb" value="Salad">Salad</input><br/>

    <br/><input type="button" value="Done" onclick="processCB()"/>
</form>
</html>