Question

I’m having a problem trying to create a Javascript function that checks all the checkboxes in a form.

An example of the checkboxes on my form look like

<b>A:</b> <input type="checkbox" name="multipleForms[201][A]"><br>
<b>B:</b> <input type="checkbox" name="multipleForms[201][B]"><br>
<b>C:</b> <input type="checkbox" name="multipleForms[201][C]"><br>
<b>D:</b> <input type="checkbox" name="multipleForms[201][D]"><br>

<b>A:</b> <input type="checkbox" name="multipleForms[500][A]"><br>
<b>B:</b> <input type="checkbox" name="multipleForms[500][B]"><br>
<b>C:</b> <input type="checkbox" name="multipleForms[500][C]"><br>

And what I want to do is be able to pass a number such as 201 and 500 into a Javascript function and have all checkboxes with the first array index as that integer be checked.

So, checkAll(201) would have the first 4 checkboxes checked and checkAll(500) would have the other 3 checkboxes checked.

I would rather not change the names of my checkboxes if that is possible as the stringed indexes are really important for my PHP code.

Thanks in advance.

Also, I would rather have non-jQuery code.

Answer 1

Something like that ? : http://jsfiddle.net/RZPNG/6/

var checkboxes = document.getElementsByTagName('input');

function check(num) {
    for (var i = 0; i < checkboxes.length; i++) {
        if (parseInt(checkboxes[i].name.split('[')[1]) === num) {
            checkboxes[i].checked = 'checked';
        }                
    }
}

check(201);​