剑三明教新手攻略:分享50个jQuery代码开发技巧（第一部分）

翻译：Terry li - GBin1.com
英文： 50 jQuery Snippets That Will Help You Become A Better JavaScript Developer

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"); 
class names: $(formToLookAt + " input:checked").each(function() {      
    keepListkeepList = keepList.filter("." + $(this).attr("name")); });

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');
  
   Item X
  
   Item Y
  
   Item Z
  
 

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");    });  });  //Now use..  $("table").delegate("td", "hover", function(){  $(this).toggleClass("hover");});
17. 找到被选择到的选项(option)元素
$('#someElement').find('option:selected');
18. 隐藏包含特定值的元素
$("p.value:contains('thetextvalue')").hide();
19. 自动的滚动到页面特定区域
jQuery.fn.autoscroll = function(selector) {  $('html,body').animate(    {scrollTop: $(selector).offset().top},    500  );}//Then to scroll to the class/area you wish to get to like this:$('.area_name').autoscroll();
20. 检测各种浏览器
$('#someElement').find('option:selected');
21. 替换字符串中的单词
var el = $('#id');el.html(el.html().replace(/word/ig, ''));
22. 关闭右键的菜单
$(document).bind('contextmenu',function(e){ return false; });
23. 定义一个定制的选择器
$.expr[':'].mycustomselector = function(element, index, meta, stack){// element- is a DOM element// index - the current loop index in stack// meta - meta data about your selector// stack - stack of all elements to loop// Return true to include current element// Return false to explude current element};// Custom Selector usage:$('.someClasses:test').doSomething();
24. 判断一个元素是否存在
if ($('#someDiv').length) {//hooray!!! it exists...}
25. 使用jQuery判断鼠标的左右键点击
$("#someelement").live('click', function(e) {    if( (!$.browser.msie && e.button == 0) || 
               ($.browser.msie && e.button == 1) ) {        alert("Left Mouse Button Clicked");    }    else if(e.button == 2)        alert("Right Mouse Button Clicked");});