function check_boxes()
{
	var ticked = $('maincheckbox').checked;
	
	var checkboxes = document.getElementsByTagName('input');

	for ( var i = 0 ; i <= checkboxes.length ; i++ )
	{
		var e = checkboxes[i];
		
		if ( typeof(e) != 'undefined' && e.type == 'checkbox')
		{
			var boxname		= e.id;
			var boxcheck	= boxname.replace( /^(.+?)_.+?$/, "$1" );
			
			if ( boxcheck == 'tid' )
			{
				e.checked = ticked;
			}			
		}
	}
}