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偶然在网上看到这些不错的jQuery代码开发技巧。原文收集了30个，另外查找的时候发现了还有20个。加上另外十个实用的jQuery代码片段，共60个代码技巧，收集在一起分享给大家。

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\");
 });
 });
 //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

Detect Safari (if( $.browser.safari)),
Detect IE6 and over (if ($.browser.msie && $.browser.version > 6 )),
Detect IE6 and below (if ($.browser.msie && $.browser.version <= 6 )),
Detect FireFox 2 and above (if ($.browser.mozilla && $.browser.version >= \'1.8\' ))

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\");
});

26. 显示或者删除输入框的缺省值

//This snippet will show you how to keep a default value
//in a text input field for when a user hasn\'t entered in
//a value to replace it
swap_val = [];
$(\".swap\").each(function(i){
 swap_val[i] = $(this).val();
 $(this).focusin(function(){
  if ($(this).val() == swap_val[i]) {
   $(this).val(\"\");
  }
 }).focusout(function(){
  if ($.trim($(this).val()) == \"\") {
   $(this).val(swap_val[i]);
  }
 });
});

<INPUT class=swap value=\"Enter Username here..\" type=text> 

27. 指定时间后自动隐藏或者关闭元素(1.4支持）

//Here\'s how we used to do it in 1.3.2 using setTimeout
setTimeout(function() {
 $(\'.mydiv\').hide(\'blind\', {}, 500)
}, 5000);
//And here\'s how you can do it with 1.4 using the delay() feature (this is a lot like sleep)
$(\".mydiv\").delay(5000).hide(\'blind\', {}, 500);

28. 动态创建元素到DOM

var newgbin1Div = $(\'\');
newgbin1Div.attr(\'id\',\'gbin1.com\').appendTo(\'body\');

29. 限制textarea的字符数量

jQuery.fn.maxLength = function(max){
 this.each(function(){
 var type = this.tagName.toLowerCase();
 var inputType = this.type? this.type.toLowerCase() : null;
 if(type == \"input\" && inputType == \"text\" || inputType == \"password\"){
  //Apply the standard maxLength
  this.maxLength = max;
 }
 else if(type == \"textarea\"){
  this.onkeypress = function(e){
  var ob = e || event;
  var keyCode = ob.keyCode;
  var hasSelection = document.selection? document.selection.createRange().text.length > 0 : this.selectionStart != this.selectionEnd;
  return !(this.value.length >= max && (keyCode > 50 || keyCode == 32 || keyCode == 0 || keyCode == 13) && !ob.ctrlKey && !ob.altKey && !hasSelection);
  };
  this.onkeyup = function(){
  if(this.value.length > max){
   this.value = this.value.substring(0,max);
  }
  };
 }
 });
};
//Usage:
$(\'#gbin1textarea\').maxLength(500);

30. 为函数创建一个基本测试用例

//Separate tests into modules.
module(\"Module B\");
test(\"some other gbin1.com test\", function() {
 //Specify how many assertions are expected to run within a test.
 expect(2);
 //A comparison assertion, equivalent to JUnit\'s assertEquals.
 equals( true, false, \"failing test\" );
 equals( true, true, \"passing test\" );
});

31. 使用jQuery克隆元素

var cloned = $(\'#gbin1div\').clone();

32. 测试一个元素在jQuery中是否可见

if($(element).is(\':visible\') == \'true\') { //The element is Visible }

33. 元素屏幕居中

jQuery.fn.center = function () {
 this.css(\'position\',\'absolute\');
 this.css(\'top\', ( $(window).height() - this.height() ) / +$(window).scrollTop() + \'px\');
 this.css(\'left\', ( $(window).width() - this.width() ) / 2+$(window).scrollLeft() + \'px\');return this;
}
//Use the above function as: $(\'#gbin1div\').center();

34. 使用特定名字的元素对应的值生成一个数组

var arrInputValues = new Array();
$(\"input[name=\'table[]\']\").each(function(){
  arrInputValues.push($(this).val());
});

35. 剔除元素中的HTML

(function($) {
 $.fn.stripHtml = function() {
  var regexp = /<(\"[^\"]*\"|\'[^\']*\'|[^\'\">])*>/gi;
  this.each(function() {
   $(this).html(
    $(this).html().replace(regexp,\"\")
   );
  });
  return $(this);
 }
})(jQuery);
//usage:
$(\'p\').stripHtml();

36. 使用closest来得到父元素

$(\'#searchBox\').closest(\'div\');

37. 使用firebug来记录jQuery事件

// Allows chainable logging
// Usage: $(\'#someDiv\').hide().log(\'div hidden\').addClass(\'someClass\');
jQuery.log = jQuery.fn.log = function (msg) {
  if (console){
   console.log(\"%s: %o\", msg, this);
  }
  return this;
};

38. 点击链接强制弹出新窗口

jQuery(\'a.popup\').live(\'click\', function(){
 newwindow=window.open($(this).attr(\'href\'),\'\',\'height=200,width=150\');
 if (window.focus) {newwindow.focus()}
 return false;
});

39. 点击链接强制打开新标签页

jQuery(\'a.newTab\').live(\'click\', function(){
 newwindow=window.open($(this).href);
 jQuery(this).target = \"_blank\";
 return false;
});

40. 使用siblings()来处理同类元素

// Rather than doing this
$(\'#nav li\').click(function(){
 $(\'#nav li\').removeClass(\'active\');
 $(this).addClass(\'active\');
});
// Do this instead
$(\'#nav li\').click(function(){
 $(this).addClass(\'active\')
  .siblings().removeClass(\'active\');
});

41. 选择或者不选页面上全部复选框

var tog = false; // or true if they are checked on load
$(\'a\').click(function() {
 $(\"input[type=checkbox]\").attr(\"checked\",!tog);
 tog = !tog;
});

42. 基于输入文字过滤页面元素

//If the value of the element matches that of the entered text
//it will be returned
$(\'.gbin1Class\').filter(function() {
 return $(this).attr(\'value\') == $(\'input#gbin1Id\').val() ;
 })

43. 取得鼠标的X和Y坐标

$(document).mousemove(function(e){
$(document).ready(function() {
$().mousemove(function(e){
$(\'#XY\').html(\"Gbin1 X Axis : \" + e.pageX + \" | Gbin1 Y Axis \" + e.pageY);
});
});

44. 使得整个列表元素(LI)可点击

$(\"ul li\").click(function(){
 window.location=$(this).find(\"a\").attr(\"href\"); return false;
});

<UL>
<LI><A href=\"#\">GBin1 Link 1</A></LI>
<LI><A href=\"#\">GBin1 Link 2</A></LI>
<LI><A href=\"#\">GBin1 Link 3</A></LI>
<LI><A href=\"#\">GBin1 Link 4</A></LI>
</UL> 

45. 使用jQuery来解析XML

function parseXml(xml) {
 //find every Tutorial and print the author
 $(xml).find(\"Tutorial\").each(function()
 {
 $(\"#output\").append($(this).attr(\"author\") + \"\");
 });
}

46. 判断一个图片是否加载完全

$(\'#theGBin1Image\').attr(\'src\', \'image.jpg\').load(function() {
alert(\'This Image Has Been Loaded\');
});

47. 使用jQuery命名事件

//Events can be namespaced like this
$(\'input\').bind(\'blur.validation\', function(e){
 // ...
});
//The data method also accept namespaces
$(\'input\').data(\'validation.isValid\', true);

48. 判断cookie是否激活或者关闭

var dt = new Date();
dt.setSeconds(dt.getSeconds() + 60);
document.cookie = \"cookietest=1; expires=\" + dt.toGMTString();
var cookiesEnabled = document.cookie.indexOf(\"cookietest=\") != -1;
if(!cookiesEnabled)
{
 //cookies have not been enabled
}

49. 强制过期cookie

var date = new Date();
date.setTime(date.getTime() + (x * 60 * 1000));
$.cookie(\'example\', \'foo\', { expires: date });

50. 使用一个可点击的链接替换页面中所有URL

$.fn.replaceUrl = function() {
  var regexp = /((ftp|http|https)://(w+:{0,1}w*@)?(S+)(:[0-9]+)?(/|/([w#!:.?+=&%@!-/]))?)/gi;
  this.each(function() {
   $(this).html(
    $(this).html().replace(regexp,\'<A href=\"$1\">$1</A>\')
   );
  });
  return $(this);
 }
//usage
$(\'#GBin1div\').replaceUrl(); 

51: 在表单中禁用“回车键”

大家可能在表单的操作中需要防止用户意外的提交表单，那么下面这段代码肯定非常有帮助：

$(\"#form\").keypress(function(e) {
 if (e.which == 13) {
 return false;
 }
});

52: 清除所有的表单数据

可能针对不同的表单形式，你需要调用不同类型的清楚方法，不过使用下面这个现成方法，绝对能让你省不少功夫。

function clearForm(form) {
 // iterate over all of the inputs for the form
 // element that was passed in
 $(\':input\', form).each(function() {
 var type = this.type;
 var tag = this.tagName.toLowerCase(); // normalize case
 // it\'s ok to reset the value attr of text inputs,
 // password inputs, and textareas
 if (type == \'text\' || type == \'password\' || tag == \'textarea\')
  this.value = \"\";
 // checkboxes and radios need to have their checked state cleared
 // but should *not* have their \'value\' changed
 else if (type == \'checkbox\' || type == \'radio\')
  this.checked = false;
 // select elements need to have their \'selectedIndex\' property set to -1
 // (this works for both single and multiple select elements)
 else if (tag == \'select\')
  this.selectedIndex = -1;
 });
};

53: 将表单中的按钮禁用

下面的代码对于ajax操作非常有用，你可以有效的避免用户多次提交数据，个人也经常使用：

禁用按钮：

$(\"#somebutton\").attr(\"disabled\", true);

启动按钮：

$(\"#submit-button\").removeAttr(\"disabled\");

可能大家往往会使用.attr(‘disabled\',false);，不过这是不正确的调用。

54: 输入内容后启用递交按钮

这个代码和上面类似，都属于帮助用户控制表单递交按钮。使用这段代码后，递交按钮只有在用户输入指定内容后才可以启动。

$(\'#username\').keyup(function() {
 $(\'#submit\').attr(\'disabled\', !$(\'#username\').val()); 
});

55: 禁止多次递交表单

多次递交表单对于web应用来说是个比较头疼的问题，下面的代码能够很好的帮助你解决这个问题：

$(document).ready(function() {
 $(\'form\').submit(function() {
 if(typeof jQuery.data(this, \"disabledOnSubmit\") == \'undefined\') {
  jQuery.data(this, \"disabledOnSubmit\", { submited: true });
  $(\'input[type=submit], input[type=button]\', this).each(function() {
  $(this).attr(\"disabled\", \"disabled\");
  });
  return true;
 }
 else
 {
  return false;
 }
 });
});

56: 高亮显示目前聚焦的输入框标示

有时候你需要提示用户目前操作的输入框，你可以使用下面代码高亮显示标示：

$(\"form :input\").focus(function() {
 $(\"label[for=\'\" + this.id + \"\']\").addClass(\"labelfocus\");
}).blur(function() {
 $(\"label\").removeClass(\"labelfocus\");
});

57: 动态方式添加表单元素

这个方法可以帮助你动态的添加表单中的元素，比如，input等：

//change event on password1 field to prompt new input
$(\'#password1\').change(function() {
  //dynamically create new input and insert after password1
  $(\"#password1\").append(\"<input type=\'text\' name=\'password2\' id=\'password2\' />\");
});

58: 自动将数据导入selectbox中

下面代码能够使用ajax数据自动生成选择框的内容

$(function(){
 $(\"select#ctlJob\").change(function(){
 $.getJSON(\"/select.php\",{id: $(this).val(), ajax: \'true\'}, function(j){
  var options = \'\';
  for (var i = 0; i < j.length; i++) {
  options += \'<option value=\"\' + j[i].optionValue + \'\">\' + j[i].optionDisplay + \'</option>\';
  }
  $(\"select#ctlPerson\").html(options);
 })
 })
})

59: 判断一个复选框是否被选中

代码很简单，如下：

$(\'#checkBox\').attr(\'checked\');

60: 使用代码来递交表单

代码很简单，如下：

$(\"#myform\").submit();