select all in check box

private void SelectAllCheckBoxControls(Control parent,bool checkedVal)
            {
            try
                {
                string strLeave=string.Empty;
                foreach (Control child in parent.Controls)
                    {
                    if (child.GetType().ToString().Equals("System.Web.UI.WebControls.CheckBox"))
                        {
                        CheckBox chk = (CheckBox)child;
                        chk.Checked=checkedVal;
                        }
                    }
                }
             catch(Exception exp)
                {
                throw new Exception("SelectAllCheckBoxControls  " + exp.Message);
                }
            }

var checkboxes = document.getElementById( 'boxes' ).getElementsByTagName( 'input' );
for ( var i = 0; i < checkboxes.length; i++ )
{
    if ( checkboxes[i].type == 'checkbox' )
    {
        checkboxes[i].chcked = true;
    }
}