Making sure at least one checkbox is checked

Question

I have a form with multiple checkboxes and I want to use JavaScript to make sure at least one is checked. This is what I have right now but no matter what is chosen an alert

Answer 1

This should work:

function valthisform()
{
    var checkboxs=document.getElementsByName("c1");
    var okay=false;
    for(var i=0,l=checkboxs.length;i

If you have a question about the code, just comment.

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^{I use l=checkboxs.length to improve the performance. See http://www.erichynds.com/javascript/javascript-loop-performance-caching-the-length-property-of-an-array/}