警报显示[对象]？

Question

I'm trying to alert an id but it shows [object Object] . How to get an ID?

$('.x3').click(function() {
  var id = $(this.id);
  alert(id);
});

Answer 1

$(this) is an DOM element . Try to access the attr property of the element.

$('.x3').click(function(){
     var id = $(this).attr("id");
     alert(id);
);

Answer 2

var id = $(this.id);

This statement simply returns a jQuery wrapper object (with length 0 if there is no matching element exists on DOM).

Stringifying it to show it on alert will print [object Object] . You rather meant to use

var id = this.id; // or var id = $(this).attr('id')