jQuery.fn.maxlength = function(){
    var maxLength = $(this).attr("maxlength");
    this.keypress(function(event){
        var key = event.which;
        if(key >= 33 || key == 13) {
            var length = this.value.length;
            if(length >= maxLength) {
                event.preventDefault();
            }
        }
    });
    this.keyup(function(){
        var length = this.value.length;
        if(length >= maxLength) {
            this.value = this.value.substr(0, maxLength)
        }
        makeDirty();
    });
}