Why is being given NoValidate attribute?

The novalidate attribute is added by jquery.validate line 32:

// Add novalidate tag if HTML5.
this.attr('novalidate', 'novalidate');

If you are using HTML5, then remove the attribute:

$("#contactForm").validate();
$("#contactForm").removeAttr("novalidate");

In your web.config, make sure you have:

 <appSettings>        
    ...
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>

Also make sure they are not commented out.