I'm performing some custom js validation on my forms, triggered by submitting the form

    $("form").submit(function (e) {
        var validates = true;
        // validation code goes in here
        if (!validates) {
            e.preventDefault();
            e.stopImmediatePropagation();
            return false;
        }
    })

None of the lines I've included to stop the submit event prevent the .NET control posting back. Is there some way (using js or setting a property in the updatepanel control) of stopping post back?