1. If errorContainer, errorLabelContainer, and wrapper are set, errorPlacement will not work
...
$(document).ready(function(){
$("#myform").validate({
errorContainer: "#messageBox1, #messageBox2",
errorLabelContainer: "#messageBox1 ul",
wrapper: "li",
debug:true,
...
errorContainer: Multiple containers can be configured. The messageBox2 element here is not packaged, but only displays and hides this element when an error occurs.
errorLabelContainer: A container that displays error information. It hides or displays the error container based on the verification results.
wrapper: The name of the outer tag that displays the error message.
errorElement: Specify the name of the html label that displays the verification error message (default is label)
For example, when errorElement is set to span