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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 = $('#shopping_cart_items input.is_in_stock');
<ul>
<li>
<input value="Item-X" type="radio"> Item X</li>
<li>
<input value="Item-Y" type="radio"> Item Y</li>
<li>
<input value="Item-Z" type="radio"> Item Z</li>
</ul>
6. 如何正确使用ToggleClass
//Toggle class allows you to add or remove a class
//from an element depending on the presence of that
//class. Where some developers would use:
a.hasClass('blueButton') ? a.removeClass('blueButton') : a.addClass('blueButton');
//toggleClass allows you to easily do this using
a.toggleClass('blueButton');
7. 设置IE指定的功能
if ($.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 }
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