25个JQuery代码技巧让你变成js高手
1. 创建一个嵌套的过滤器

.filter(":not(:has(.selected))") //去掉所有不包含class为.selected的元素
2. 重用你的元素查询

var allItems = $("div.item"); 
var keepList = $("div#container1 div.item");
<div>class names:
$(formToLookAt + " input:checked").each(function() {     keepListkeepList = keepList.filter("." + $(this).attr("name")); });
</div>
3. 使用has()来判断一个元素是否包含特定的class或者元素

//jQuery 1.4.* includes support for the has method. This method will find 
//if a an element contains a certain other element class or whatever it is 
//you are looking for and do anything you want to them.
$("input").has(".email").addClass("email_icon");
4. 使用jQuery切换样式

//Look for the media-type you wish to switch then set the href to your new style sheet 
$('link[media='screen']').attr('href', 'Alternative.css'); 
5. 限制选择的区域

//Where possible, pre-fix your class names with a tag name 
//so that jQuery doesn't have to spend more time searching 
//for the element you're after. Also remember that anything 
//you can do to be more specific about where the element is 
//on your page will cut down on execution/search times 
var in_stock = $('#shopping_cart_items input.is_in_stock');
<ul id="shopping_cart_items"> 
<li> 
<input value="Item-X" name="item" class="is_in_stock" type="radio"> Item X</li> 
<li> 
<input value="Item-Y" name="item" class="3-5_days" type="radio"> Item Y</li> 
<li> 
<input value="Item-Z" name="item" class="unknown" type="radio"> Item Z</li> 
</ul>
6. 如何正确使用ToggleClass

//Toggle class allows you to add or remove a class 
//from an element depending on the presence of that 
//class. Where some developers would use: 
a.hasClass('blueButton') ? a.removeClass('blueButton') : a.addClass('blueButton'); 
//toggleClass allows you to easily do this using 
a.toggleClass('blueButton');


7. 设置IE指定的功能

if ($.browser.msie) { // Internet Explorer is a sadist. }
8. 使用jQuery来替换一个元素

$('#thatdiv').replaceWith('fnuh');
9. 验证一个元素是否为空

if ($('#keks').html()) { //Nothing found ;} 
10. 在无序的set中查找一个元素的索引

$("ul > li").click(function () { 
    var index = $(this).prevAll().length; 
});
11. 绑定一个函数到一个事件

$('#foo').bind('click', function() { 
  alert('User clicked on "foo."'); 
});
12. 添加HTML到一个元素

$('#lal').append('sometext');
13. 创建元素时使用对象来定义属性

var e = $("", { href: "#", class: "a-class another-class", title: "..." });
14. 使用过滤器过滤多属性

//This precision-based approached can be useful when you use 
//lots of similar input elements which have different types 
var elements = $('#someid input[type=sometype][value=somevalue]').get();
15. 使用jQuery预加载图片

jQuery.preloadImages = function() { for(var i = 0; i').attr('src', arguments[i]); } }; 
// Usage $.preloadImages('image1.gif', '/path/to/image2.png', 'some/image3.jpg');  
16. 设置任何匹配一个选择器的事件处理程序

$('button.someClass').live('click', someFunction);
  //Note that in jQuery 1.4.2, the delegate and undelegate options have been
  //introduced to replace live as they offer better support for context
    //For example, in terms of a table where before you would use..
  // .live()
  $("table").each(function(){
    $("td", this).live("hover", function(){
    $(this).toggleClass("hover");
    });