Delete Selected Checkbox items from the database. HELP

[eluser]basty_dread[/eluser]
i can't get it on how to use javascript to check all or uncheck the checkboxes using this name with brackets

Code:

<input type="checkbox" name="rdindex1[]" value="<?=$primeno[$i];?>"/>

the javascript only works if the

Code:

name="rdindex1"

what should i do?
this is my javascript for checking all the checkbox:

Code:

function checkallBox()
{
    for (i=0;i<document.forms['formkeywords'].rdindex1.length;i++)
    {
        document.forms['formkeywords'].rdindex1[i].checked=true;
                                                                       }
}