$("table.planning_grid td").live({
  mouseenter:function(){
     $(this).parent("tr").find("a.delete").show();
  },
  mouseleave:function(){
     $(this).parent("tr").find("a.delete").hide();
  },
  click:function(){
    //do something else.
  }
});

$("table.planning_grid td").on({
    mouseenter:function(){  //see above
    },
    mouseleave:function(){ //see above
    }
    click:function(){ //etc
    }
  });

$("table.planning_grid").on('mouseenter','td',function(){});

$("table.planning_grid").on('td',{
   mouseenter: function(){ /* event1 */ },
   mouseleave: function(){ /* event2 */ },
   click: function(){  /* event3 */ }
 });

$("table.planning_grid").on({
    mouseenter: function() {
        // Handle mouseenter...
    },
    mouseleave: function() {
        // Handle mouseleave...
    },
    click: function() {
        // Handle click...
    }
}, "td");

$('table.planning_grid').on('mouseenter mouseleave', function() {
    //JS Code
});

$("table.planning_grid").on({
    mouseenter: function() {
        // Handle mouseenter...
    },
    mouseleave: function() {
        // Handle mouseleave...
    },
    'click blur paste' : function() {
        // Handle click...
    }
}, "input");

function showPhotos() {
    $(this).find("span").slideToggle();
}

$(".photos")
    .on("mouseenter", "li", showPhotos)
    .on("mouseleave", "li", showPhotos);

$("textarea[id^='options_'],input[id^='options_']").on('keyup onmouseout keydown keypress blur change',
  function() {

  }
);

$('input').on('keyup blur focus', function () {