在使用jQuery模糊之后，如何检查焦点是否已切换到新元素？

Question

I have a text input on my page. When it receives focus, a select box appears underneath it. When it loses focus, I want the select box to disappear unless the focus has shifted to the select box. Sounds simple enough but I struck a problem.

I set up the event handlers like so (using coffeescript)

jQuery ->
  $('td.description input').focus -> showItemSelector()
  $('td.description input').blur -> hideItemSelector()

showItemSelector() and hideItemSelector() are defined like so

showItemSelector () ->
  $('#item-selector').show()

hideItemSelector () ->
  unless $('#item-selector select').is(':focus')
    $('#item-selector').hide()

But it doesn't work. The item selector is always hidden after the input loses focus. I did some experimenting and my suspicion was confirmed. The hideItemSelector function is being executed before focus is shifted to the new element (which makes some sense - the browser presumably takes focus from the first element, triggering my function, before it assigns focus to the next element). The following bit of code demonstrates this;

hideItemSelector = () ->
    focus = -> console.log $('select#category').is(':focus')
    focus()
    setTimeout focus, 1000

This returns false and then true in the console. The delay gives the browser time to shift the focus.

So my question is, how can I do what I want to do without using a setTimeout? If nothing else works then this will have to do, but it seems like a flawed approach.

Answer 1

You can achieve this with assigning global var and changing its value from true to false as a user moves on and off the object, for example:

$('#yourElement').mouseenter(function() {
  isHovered = true;
}).mouseleave(function() {
   isHovered = false;
 });

There is also a way that works in all browsers except Internet Explorer but I wouldn't recommend using it as it's using invalid pseudo-selector:

if ($('#hello').is(':hover')) {
      alert('hello');
 }

Other than that you will have to find plugins for that. Here is the self made plugin by SpYk3HH which can be found here: jsFiddle isHover Plugin Demo . I would also recommend reading: How do I check if the mouse is over an element in jQuery? . I think it will be useful to you.