snippet.js

    $("form").each(function(idx, form) {
      var onsubmit = $(form).attr("onsubmit");
      
      if(typeof(onsubmit) !== undefined) {
        $(form).removeAttr("onsubmit"); // this properly removes the attribute; nothing within this is triggered
        $(form).submit(function() {
          alert("submitted!"); // this doesn't get called
        });
      }
    });