How to skin all ASP.Net validators?

I want all of the validators in an ASP.Net 3.5 website to have a CssClass value of "error". My initial thought was to do this in a theme skin like so:

<asp:CompareValidator runat="server" 
    CssClass="error" />
<asp:CustomValidator runat="server" 
    CssClass="error" />
<asp:RequiredFieldValidator runat="server" 
    CssClass="error" />
<belCommon:ZipCodeValidator runat="server" 
    CssClass="error" />
<belCommon:PhoneNumberValidator runat="server" 
    CssClass="error" />

This is only a partial listing of validators that I use. Ideally, I would like to do something like this:

<asp:BaseValidator runat="server" 
    CssClass="error" />

And because all validators inherit from BaseValidator, I would expect that this would work, but it doesn't. Is there a way to accomplish this without adding every single validator control to the skin explicitly?

Update:

I found a different approach using javascript:

Sys.Application.add_init(function(sender, args)
{
    if (Page_Validators != null)
    {
        for (i = 0; i < Page_Validators.length; i++)
        {
            Page_Validators[i].className = "error";
        }
    }
});

ASP.Net generates a javascript variable called Page_Validators, which is an array of the validation spans. This script checks to see if it exists and then loops through and sets the class name. I added this to the master page and its working so far.

Solution

I found a different approach using javascript:

Sys.Application.add_init(function(sender, args)
{
    if (Page_Validators != null)
    {
        for (i = 0; i < Page_Validators.length; i++)
        {
            Page_Validators[i].className = "error";
        }
    }
});