How to implement “select all” check box in HTML?

Question

I have an HTML page with multiple checkboxes.

I need one more checkbox by the name \"select all\". When I select this checkbox all checkboxes in the HTML page must b

Answer 1

You may have different sets of checkboxes on the same form. Here is a solution that selects/unselects checkboxes by class name, using vanilla javascript function document.getElementsByClassName

The Select All button

 Select All

Some of the checkboxes to select

The javascript

    function selectAll() {
        var blnChecked = document.getElementById("select_all_invoices").checked;
        var check_invoices = document.getElementsByClassName("check_invoice");
        var intLength = check_invoices.length;
        for(var i = 0; i < intLength; i++) {
            var check_invoice = check_invoices[i];
            check_invoice.checked = blnChecked;
        }
    }