Replace text with multiple boxes

I'm starting with jQuery and I need this is a project.

For example I have this:

<ul id="grid">
  <li class="box1">Lorem ipsum dolor sit amet!</li>
  <li class="box2">Lorem ipsum dolor sit amet!</li>
  <li class="box3">Lorem ipsum dolor sit amet!</li>
</ul>

And Information for the grid items

<div class="box_info_1">Info for grid item</div>
<div class="box_info_2">Info for grid item</div>
<div class="box_info_3">Info for grid item</div>

And a div:

<div id="promo">开发者_StackOverflow社区;I want to set grid info here</div>

What i want to accomplish is when I hover over a box, the promo div replaces the content with the corresponding info_box

So when I hover over box1, i want the content of box_info_1 in the promo div

---

I love to use data element selectors, and so can you!

Data elements are part of the HTML5 standard, seen here, allowing a user to associate ad-hoc data with any element. They are available in all modern browsers. Further, jQuery defines a simple standard to read and write to data attributes through the $.data() function. The following example stores a CSS-selector in a data-element for each element, and then references it when implementing the hover handler.

First, tell each "box" which box-info element it is assigned to (we'll use a CSS-selector in a data attribute), as follow:

 <ul id="grid">
   <li class="box box1" data-item=".box_info_1">Lorem ipsum dolor sit amet!</li>
   <li class="box box2" data-item=".box_info_2">Lorem ipsum dolor sit amet!</li>
   <li class="box box3" data-item=".box_info_3">Lorem ipsum dolor sit amet!</li>
 </ul>

Then use the following JavaScript to get the element and replace the contents of promo:

 $('.box').hover(function() {
   $('#promo').text($($(this).data('item')).text());
 });

---

$('.box1').hover(function(){
    $('#promo').text($('.box_info_1').text());
});

Or, for all the boxes

$('#grid li').hover(function(){
    var currentNumber = $(this).attr('class').substr(3);
    var currentText = $('.box_info_'+currentNumber).text();
    $('#promo').text(currentText);
});

---

var txt = $('#promo').text();
$('#grid li').hover(function() {
    var boxIndex = $('#grid li').index(this);
    $('#promo').empty().text($('.box_info_' + (boxIndex + 1) + '').text());
},
function() {
    $('#promo').empty().text(txt);
});