SOURCE

$("div.left, div.right").find("div, div > p").addClass("border");


$("div.before-addback").find("p").addClass("background");


$("div.after-addback").find("p").addBack().addClass("background");


$("div.left").one('click',function () {
    console.log('left one click ')
})

$("#old").click(function(){
  $("input").trigger("focus");
});
$("#new").click(function(){
  $("input").triggerHandler('blur');
});
$("input").focus(function(){
  $("<span>Focused!</span>").appendTo("body").fadeOut(10000);
});

$("input").click(function(){
  $(this).val(10000);
});

$("p").focusin(function() {
  $(this).find("span").css('display','inline').fadeOut(1000);
});

$("p").slideDown("fast",function(){
   console.log("Animation Done.");
 });

 $("#new").fadeToggle(function (){
     console.log(37,$(this))
     $(this).animate({
         opacity:'toggle'
     },1e3)
 })

console.log($.fn.jquery)


let cc = document.getElementById('cc') 
let child = cc.children 

console.log(46,cc , child)

for(let i = 0 ; i < child.length ; i++) {
    let c = child[i]
    c.addEventListener('click',function (event) { 
        let type = event.target.innerText
        console.log(55,'click1',type)
        event[type]()
    })
    c.addEventListener('click',function (event) { 
        let type = event.target.innerText
        console.log(55,'click2',type)
    })
    c.addEventListener('mousedown',function (event) { 
        let type = event.target.innerText
        console.log(55,'mousedown',type)
    })
}

cc.addEventListener('click',function (event) {
    let t = event.target.innerText 
    console.log('div',t)
})

document.body.addEventListener('click',function (event) {
    console.log(65,'body click')
})

 $('#whichkey').bind('keydown',function(e){
 $('#log').html(e.type + ': ' +  e.which );  });

<div class="left">
  <p><strong>Before <code>addBack()</code></strong></p>
  <div class="before-addback">
    <p>First Paragraph</p>
    <p>Second Paragraph</p>
  </div>
</div>
<div class="right">
  <p><strong>After <code>addBack()</code></strong></p>
  <div class="after-addback">
    <p>First Paragraph <input type="text" /> <span>focusout fire</span> </p>
    <p>Second Paragraph <input type="password" /> <span>focusout fire</span></p>
  </div>
</div>

1.9版本 .toggle(function, function, … ) 方法删除,jQuery Migrate（迁移）插件可以恢复此功能。
<button id="old">.trigger("focus")</button>
<button id="new">.triggerHandler("focus")</button><br/><br/>
<input type="text" value="To Be Focused"/>

<div id='cc' >
    <p> preventDefault  </p>
    <p>stopImmediatePropagation </p>
    <p>stopPropagation</p>
</div>

<div>
    <input id="whichkey" value="type something">
      <div id="log"></div>
</div>

p, div { margin:5px; padding:5px; }
.border { border: 2px solid red; }
.background { background:yellow; }
.left, .right { width: 45%; float: left;}
.right { margin-left:3%; }

#cc{ border: 1px solid red;}