Pardon the mixing of comment formats.
// must be non-blank - values are digits <select name="port" id="port" class="{required: true}" >...</select> // "Port not found" in previous list - values are strings <select name="country" id="country" class="{required: '#port[value=-1]'}">...</select> // "Port not found" in previous list - value is a string <input name="new_port" id="new_port" class="{required: '#port[value=0]'}"/> // "Port not found" AND "Country not found" - how do I require both? <input name="new_country" id="new_country" class="{required: '#country[value=]'}"/> Can I do this as a class definition? Sud.