60個很實用的jQuery代碼開發技巧收集
編輯：JQuery特效代碼
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偶然在網上看到這些不錯的jQuery代碼開發技巧。原文收集了30個，另外查找的時候發現了還有20個。加上另外十個實用的jQuery代碼片段，共60個代碼技巧，收集在一起分享給大家。
1. 創建一個嵌套的過濾器
.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
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
//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
//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
//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 = $('#shopping_cart_items input.is_in_stock');
<ul id="shopping_cart_items"> <li> <input value="Item-X" name="item" class="is_in_stock" type="radio"> Item X</li> <li> <input value="Item-Y" name="item" class="3-5_days" type="radio"> Item Y</li> <li> <input value="Item-Z" name="item" class="unknown" type="radio"> Item Z</li> </ul>
6. 如何正確使用ToggleClass
//Toggle class allows you to add or remove a class
//from an element depending on the presence of that
//class. Where some developers would use:
a.hasClass('blueButton') ? a.removeClass('blueButton') : a.addClass('blueButton');
//toggleClass allows you to easily do this using
a.toggleClass('blueButton');
7. 設置IE指定的功能
if ($.browser.msie) { // Internet Explorer is a sadist. }
8. 使用jQuery來替換一個元素
$('#thatdiv').replaceWith('fnuh');
9. 驗證一個元素是否為空
if ($('#keks').html()) { //Nothing found ;}
10. 在無序的set中查找一個元素的索引
$("ul > li").click(function () {
var index = $(this).prevAll().length;
});
11. 綁定一個函數到一個事件
$('#foo').bind('click', function() {
alert('User clicked on "foo."');
});
12. 添加HTML到一個元素
$('#lal').append('sometext');
13. 創建元素時使用對象來定義屬性
var e = $("", { href: "#", class: "a-class another-class", title: "..." });
14. 使用過濾器過濾多屬性
//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預加載圖片
jQuery.preloadImages = function() { for(var i = 0; i').attr('src', arguments[i]); } };
// Usage $.preloadImages('image1.gif', '/path/to/image2.png', 'some/image3.jpg');
16. 設置任何匹配一個選擇器的事件處理程序
$('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. 找到被選擇到的選項(option)元素
$('#someElement').find('option:selected');
18. 隱藏包含特定值的元素
$("p.value:contains('thetextvalue')").hide();
19. 自動的滾動到頁面特定區域
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. 檢測各種浏覽器
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. 替換字符串中的單詞
var el = $('#id');
el.html(el.html().replace(/word/ig, ''));
22. 關閉右鍵的菜單
$(document).bind('contextmenu',function(e){ return false; });
23. 定義一個定制的選擇器
$.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:
$('.someClasses:test').doSomething();
24. 判斷一個元素是否存在
if ($('#someDiv').length) {//hooray!!! it exists...}
25. 使用jQuery判斷鼠標的左右鍵點擊
$("#someelement").live('click', function(e) {
if( (!$.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
//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. 指定時間後自動隱藏或者關閉元素(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. 動態創建元素到DOM
var newgbin1Div = $('');
newgbin1Div.attr('id','gbin1.com').appendTo('body');
29. 限制textarea的字符數量
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. 為函數創建一個基本測試用例
//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 = $('#gbin1div').clone();
32. 測試一個元素在jQuery中是否可見
if($(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對應的值生成一個數組
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來得到父元素
$('#searchBox').closest('div');
37. 使用firebug來記錄jQuery事件
// Allows chainable logging
// Usage: $('#someDiv').hide().log('div hidden').addClass('someClass');
jQuery.log = jQuery.fn.log = function (msg) {
if (console){
console.log("%s: %o", msg, this);
}
return this;
};
38. 點擊鏈接強制彈出新窗口
jQuery('a.popup').live('click', function(){
newwindow=window.open($(this).attr('href'),'','height=200,width=150');
if (window.focus) {newwindow.focus()}
return false;
});
39. 點擊鏈接強制打開新標簽頁
jQuery('a.newTab').live('click', function(){
newwindow=window.open($(this).href);
jQuery(this).target = "_blank";
return false;
});
40. 使用siblings()來處理同類元素
// 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. 選擇或者不選頁面上全部復選框
var tog = false; // or true if they are checked on load
$('a').click(function() {
$("input[type=checkbox]").attr("checked",!tog);
tog = !tog;
});
42. 基於輸入文字過濾頁面元素
//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. 取得鼠標的X和Y坐標
$(document).mousemove(function(e){
$(document).ready(function() {
$().mousemove(function(e){
$('#XY').html("Gbin1 X Axis : " + e.pageX + " | Gbin1 Y Axis " + e.pageY);
});
});
44. 使得整個列表元素(LI)可點擊
$("ul li").click(function(){
window.location=$(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來解析XML
function parseXml(xml) {
//find every Tutorial and print the author
$(xml).find("Tutorial").each(function()
{
$("#output").append($(this).attr("author") + "");
});
}
46. 判斷一個圖片是否加載完全
$('#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. 判斷cookie是否激活或者關閉
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. 強制過期cookie
var date = new Date();
date.setTime(date.getTime() + (x * 60 * 1000));
$.cookie('example', 'foo', { expires: date });
50. 使用一個可點擊的鏈接替換頁面中所有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: 在表單中禁用“回車鍵”
大家可能在表單的操作中需要防止用戶意外的提交表單，那麼下面這段代碼肯定非常有幫助：
$("#form").keypress(function(e) {
if (e.which == 13) {
return false;
}
});
52: 清除所有的表單數據
可能針對不同的表單形式，你需要調用不同類型的清楚方法，不過使用下面這個現成方法，絕對能讓你省不少功夫。
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: 將表單中的按鈕禁用
下面的代碼對於ajax操作非常有用，你可以有效的避免用戶多次提交數據，個人也經常使用：
禁用按鈕：
$("#somebutton").attr("disabled", true);
啟動按鈕：
$("#submit-button").removeAttr("disabled");
可能大家往往會使用.attr(‘disabled',false);，不過這是不正確的調用。
54: 輸入內容後啟用遞交按鈕
這個代碼和上面類似，都屬於幫助用戶控制表單遞交按鈕。使用這段代碼後，遞交按鈕只有在用戶輸入指定內容後才可以啟動。
$('#username').keyup(function() {
$('#submit').attr('disabled', !$('#username').val());
});
55: 禁止多次遞交表單
多次遞交表單對於web應用來說是個比較頭疼的問題，下面的代碼能夠很好的幫助你解決這個問題：
$(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: 高亮顯示目前聚焦的輸入框標示
有時候你需要提示用戶目前操作的輸入框，你可以使用下面代碼高亮顯示標示：
$("form :input").focus(function() {
$("label[for='" + this.id + "']").addClass("labelfocus");
}).blur(function() {
$("label").removeClass("labelfocus");
});
57: 動態方式添加表單元素
這個方法可以幫助你動態的添加表單中的元素，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: 自動將數據導入selectbox中
下面代碼能夠使用ajax數據自動生成選擇框的內容
$(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: 判斷一個復選框是否被選中
代碼很簡單，如下：
$('#checkBox').attr('checked');
60: 使用代碼來遞交表單
代碼很簡單，如下：
$("#myform").submit();
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