validate the number

validate the number

Hi,

i have the field where the user needs to enter the number in.  How's can i validate and make sure the number  < 30?  Not sure how to add the syntax to the code below for this validate, please help?

$ (document) .ready (function () {
        $ ( "#getpo" ) .validate ({
      rules: {
                supplier_No: {required: true},
                lot: {required: true, number :true}
        
            }
        });
    });

Thanks