本文實例總結了30個經典的jQuery代碼開發技巧。分享給大家供大家參考。具體如下：
1. 創建一個嵌套的過濾器
代碼如下:.filter(":not(:has(.selected))") //去掉所有不包含class為.selected的元素
2. 重用你的元素查詢
代碼如下: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()來判斷一個元素是否包含特定的class或者元素
代碼如下://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切換樣式
代碼如下://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. 限制選擇的區域
代碼如下://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 = $('#shopping_cart_items input.is_in_stock');
<ul id="shopping_cart_items">
<li> <input value="Item-X" name="item" type="radio"> Item X</li>
<li> <input value="Item-Y" name="item" type="radio"> Item Y</li>
<li> <input value="Item-Z" name="item" type="radio"> Item Z</li>
</ul>
6. 如何正確使用ToggleClass
代碼如下://Toggle class allows you to add or remove a class
//from an element depending on the presence of that
//class. Where some developers would use:
a.hasClass('blueButton') ? a.removeClass('blueButton') : a.addClass('blueButton');
//toggleClass allows you to easily do this usinga.toggleClass('blueButton');
7. 設置IE指定的功能
代碼如下:if ($.browser.msie) {
// Internet Explorer is a sadist.
}
8. 使用jQuery來替換一個元素
代碼如下:$('#thatdiv').replaceWith('fnuh');
9. 驗證一個元素是否為空
代碼如下:if ($('#keks').html()) {
//Nothing found ;
}
10. 在無序的set中查找一個元素的索引
代碼如下:$("ul > li").click(function () { var index = $(this).prevAll().length; });
11. 綁定一個函數到一個事件
代碼如下:$('#foo').bind('click', function() { alert('User clicked on "foo."'); });
12. 添加HTML到一個元素
代碼如下:$('#lal').append('sometext');
13. 創建元素時使用對象來定義屬性
代碼如下:var e = $("", { href: "#", class: "a-class another-class", title: "..." });
14. 使用過濾器過濾多屬性
代碼如下://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預加載圖片
代碼如下:jQuery.preloadImages = function() { for(var i = 0; i').attr('src', arguments[i]); } };
// Usage $.preloadImages('image1.gif', '/path/to/image2.png', 'some/image3.jpg');
16. 設置任何匹配一個選擇器的事件處理程序
[code]$('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(){ $(this).toggleClass("hover"); });
17. 找到被選擇到的選項(option)元素
代碼如下:$('#someElement').find('option:selected');
18. 隱藏包含特定值的元素
代碼如下:$("p.value:contains('thetextvalue')").hide();
19. 自動的滾動到頁面特定區域
代碼如下: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. 檢測各種浏覽器
代碼如下: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. 替換字符串中的單詞
代碼如下:var el = $('#id'); el.html(el.html().replace(/word/ig, ''));
22. 關閉右鍵的菜單
代碼如下:$(document).bind('contextmenu',function(e){ return false; });
23. 定義一個定制的選擇器
代碼如下:$.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:
$('.someClasses:test').doSomething();
24. 判斷一個元素是否存在
代碼如下:if ($('#someDiv').length) {
//hooray!!! it exists...
}
25. 使用jQuery判斷鼠標的左右鍵點擊
代碼如下:$("#someelement").live('click', function(e) { if( (!$.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. 顯示或者刪除輸入框的缺省值
代碼如下://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 value="Enter Username here.." type=text>
27. 指定時間後自動隱藏或者關閉元素(1.4支持）
代碼如下://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. 動態創建元素到DOM
代碼如下:var newgbin1Div = $('');
newgbin1Div.attr('id','gbin1.com').appendTo('body');
29. 限制textarea的字符數量
代碼如下: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. 為函數創建一個基本測試用例
代碼如下://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" );
});
希望本文所述對大家的jquery程序設計有所幫助。