JavaScript to select all checkboxes

function selectAll(obj) {
    var checkboxCount = 0;
    for(i=0;i<document.forms[0].elements.length;i++) {
        if(document.forms[0].elements[i].name=="auditLogIds") {
            checkboxCount++;
            if(checkboxCount > 1) {
                break;
            }
        }
    }
    if(checkboxCount > 1) {
        for(i=0;i<document.forms[0].auditLogIds.length;i++) {
            document.forms[0].auditLogIds[i].checked=obj.checked;
        }
    }
    else {
        document.forms[0].auditLogIds.checked=obj.checked;
    }
    return;
}