using a custom jQuery validation class

I have some custom validation I'd like to do with jQuery. jQuery validation comes out of the box with a 'required' class. This means that I can have a script declaring

$('form').validate()

and the next textbox will validate correctly, based on the class 'required' I add to it:

<input type="text" value="" name="flowstatus" id="flowstatus" class="required">

My new validation rule is: the text in a textbox should be between 15 and 50 chars long. Is there a way to create my own custom rul开发者_StackOverflowe/class to implement something like

<input type="text" value="" name="flowstatus" id="flowstatus" class="from15to50">

Note: This is NOT what I need:

('form').validate({
    rules: {
        flowstatus: {required: true, minlength: 15, maxlength: 50}
}}); 

This last script is too tightly coupled to the fields I want to validate.

I'm pretty sure that you can add an attribute to the desired element defining its min and max lengths. Something like:

<input type="text" value="" name="flowstatus" id="flowstatus" class="required" minlength="15" maxlength="50">

I'm not quite sure about the custom class solution, however.