jQuery disable rule validation on a single field

Just add the ignore rule and define the selector. In this example, the validation will ignore all elements that have the class="ignore"

$("#myform").validate({
   ignore: ".ignore"
})

If you're using ASP.NET MVC Unobtrusive JQuery validation you need to set the settings in this way. This is because of the way Microsoft actually calls jQuery validate. This should be safe to do inside a ready method.

Edit: Please see Cory's comment below before copy pasting this. This is my original code

    $("form").data("validator").settings.ignore = ".data-val-ignore, :hidden, :disabled";

Then I just apply .data-val-ignore class to things not to validate.

Note that you'll probably want to add :hidden which is actually the default ignore behavior defined in jquery.validate.js. I like to add :disabled too.

$.extend($.validator, {
defaults: {
    messages: {},
    groups: {},
    rules: {},
    errorClass: "error",
    validClass: "valid",
    errorElement: "label",
    focusInvalid: true,
    errorContainer: $([]),
    errorLabelContainer: $([]),
    onsubmit: true,
    ignore: ":hidden",              // default for ignore in jquery.validate.js
    ignoreTitle: false,
    onfocusin: function( element, event ) {
        this.lastActive = element;

And finally you may want to style it - especially useful during debugging.

.data-val-ignore
{
    background: #eee;
}

Following on Gabe's answer, you can also set the ignore value as a default, so you don't have to set it on each form.

$.validator.setDefaults({ignore: ".ignore"});

Also note, the ignore field is a jQuery selector that is used in the jQuery not() function so any valid selector can be used, not just simple classes.

See also http://docs.jquery.com/Plugins/Validation/validate#toptions for details on other default values that can be set.