Comprehensive and detailed jQuery common development skills manual_jquery

This article has compiled a very detailed article on common jQuery development techniques for your reference. The specific content is as follows

1. References about page elements
Referencing elements through jquery's $() includes methods such as id, class, element name, hierarchical relationship of elements, dom or xpath conditions, etc., and the returned object is a jquery object (collection object), which cannot be directly called dom-defined method.

2. Conversion of jQuery objects and dom objects
Only jquery objects can use the methods defined by jquery. Note that there is a difference between dom objects and jquery objects. When calling methods, you should pay attention to whether you are operating on dom objects or jquery objects.
Ordinary DOM objects can generally be converted into jQuery objects through $().
For example: $(document.getElementById("msg")) is a jquery object, and you can use jquery methods.
Since the jquery object itself is a collection. Therefore, if the jquery object is to be converted into a dom object, one of the items must be retrieved, which can generally be retrieved through an index.
For example: $("#msg")[0], $("div").eq(1)[0], $("div").get()[1], $("td")[5 ] These are dom objects, and you can use methods in dom, but you can no longer use Jquery methods.
The following ways of writing are all correct:

The code is as follows:

$("#msg").html(); 
$("#msg")[0].innerHTML; 
$("#msg").eq(0)[0].innerHTML; 
$("#msg").get(0).innerHTML;

3. How to get an item of jQuery collection
For the obtained element set, you can use the eq or get(n) method or index number to obtain an item (specified by index). Please note that eq returns a jquery object, and get(n) and The index returns the dom element object. For jquery objects, you can only use jquery methods, and for dom objects, you can only use dom methods. For example, you want to get the content of the third

element. There are two methods:

$(“div”).eq(2).html(); //调用jquery对象的方法 
$(“div”).get(2).innerHTML; //调用dom的方法属性 

4. The same function implements set and get
This is true for many methods in Jquery, mainly including the following:

The code is as follows:

$(“#msg”).html(); //返回id为msg的元素节点的html内容。 
$(“#msg”).html(“<b>new content</b>”); 
//将“<b>new content</b>” 作为html串写入id为msg的元素节点内容中,页面显示粗体的new content 
$(“#msg”).text(); //返回id为msg的元素节点的文本内容。 
$(“#msg”).text(“<b>new content</b>”); 
//将“<b>new content</b>” 作为普通文本串写入id为msg的元素节点内容中,页面显示<b>new content</b> 
$(“#msg”).height(); //返回id为msg的元素的高度 
$(“#msg”).height(“300″); //将id为msg的元素的高度设为300 
$(“#msg”).width(); //返回id为msg的元素的宽度 
$(“#msg”).width(“300″); //将id为msg的元素的宽度设为300 
$(“input”).val(“); //返回表单输入框的value值 
$(“input”).val(“test”); //将表单输入框的value值设为test 
$(“#msg”).click(); //触发id为msg的元素的单击事件 
$(“#msg”).click(fn); //为id为msg的元素单击事件添加函数

Similarly, blur, focus, select, and submit events can have two calling methods

5. Collection processing function
For the collection content returned by jquery, we do not need to loop through it ourselves and process each object separately. jquery has provided us with a very convenient method to process the collection.
Includes two forms:

The code is as follows:

$(“p”).each(function(i){this.style.color=['#f00','#0f0','#00f'][ i ]}) 
//为索引分别为0，1，2的p元素分别设定不同的字体颜色。 
$(“tr”).each(function(i){this.style.backgroundColor=['#ccc','#fff'][i%2]}) 
//实现表格的隔行换色效果 www.222gs.com 
$(“p”).click(function(){alert($(this).html())}) 
//为每个p元素增加了click事件，单击某个p元素则弹出其内容

6. Expand the functions we need

The code is as follows:

$.extend({ 
min: function(a, b){return a < b&#63;a:b; }, 
max: function(a, b){return a > b&#63;a:b; } 
}); //为jquery扩展了min,max两个方法 

Use extended methods (called via "$.methodname"):

alert(“a=10,b=20,max=”+$.max(10,20)+”,min=”+$.min(10,20));

7. Support method concatenation
The so-called continuous writing means that you can continuously call various methods on a jquery object.
For example:

The code is as follows:

$(“p”).click(function(){alert($(this).html())}) 
.mouseover(function(){alert(‘mouse over event')}) 
.each(function(i){this.style.color=['#f00','#0f0','#00f'][ i ]});

8. Style of operating elements
Mainly include the following methods:

The code is as follows:

$(“#msg”).css(“background”); //返回元素的背景颜色 
$(“#msg”).css(“background”,”#ccc”) //设定元素背景为灰色 
$(“#msg”).height(300); $(“#msg”).width(“200″); //设定宽高 
$(“#msg”).css({ color: “red”, background: “blue” });//以名值对的形式设定样式 
$(“#msg”).addClass(“select”); //为元素增加名称为select的class 
$(“#msg”).removeClass(“select”); //删除元素名称为select的class 
$(“#msg”).toggleClass(“select”); //如果存在（不存在）就删除（添加）名称为select的class

9. Complete event processing function
Jquery has provided us with various event handling methods. We do not need to write events directly on html elements, but can directly add events to objects obtained through jquery.
Such as:

The code is as follows:

$(“#msg”).click(function(){alert(“good”)}) //为元素添加了单击事件 
$(“p”).click(function(i){this.style.color=['#f00','#0f0','#00f'][ i ]}) 
//为三个不同的p元素单击事件分别设定不同的处理

Several custom events in jQuery:
(1)hover(fn1,fn2): A method that simulates hover events (the mouse moves over an object and out of the object). When the mouse moves over a matching element, the first specified function will be triggered. When the mouse moves out of this element, the specified second function will be triggered.

The code is as follows:

//当鼠标放在表格的某行上时将class置为over，离开时置为out。 
$(“tr”).hover(function(){ 
$(this).addClass(“over”); 
}, 
function(){ 
$(this).addClass(“out”); 
});

(2) ready(fn): Bind a function to be executed when the DOM is loaded and ready for query and manipulation.

The code is as follows:

$(document).ready(function(){alert(“Load Success”)})

//页面加载完毕提示“Load Success”,相当于onload事件，与$(fn)等价 

(3) toggle(evenFn,oddFn): Switch the function to be called every time you click. If a matching element is clicked, the first function specified is triggered, and when the same element is clicked again, the second function specified is triggered. Each subsequent click repeats the call to these two functions in turn.

The code is as follows:

//每次点击时轮换添加和删除名为selected的class。 
$(“p”).toggle(function(){ 
$(this).addClass(“selected”); 
},function(){ 
$(this).removeClass(“selected”); 
});

(4) trigger(eventtype): Trigger a certain type of event on each matching element.
For example:
$("p").trigger("click"); //Trigger the click event of all p elements
(5) bind(eventtype,fn), unbind(eventtype): binding and unbinding of events
Removes (adds) the bound event from each matching element.
For example:

The code is as follows:

$(“p”).bind(“click”, function(){alert($(this).text());}); //为每个p元素添加单击事件 
$(“p”).unbind(); //删除所有p元素上的所有事件 
$(“p”).unbind(“click”) //删除所有p元素上的单击事件

10、几个实用特效功能
其中toggle()和slidetoggle()方法提供了状态切换功能。
如toggle()方法包括了hide()和show()方法。
slideToggle()方法包括了slideDown()和slideUp方法。
11、几个有用的jQuery方法
$.browser.浏览器类型：检测浏览器类型。有效参数：safari, opera, msie, mozilla。如检测是否ie：$.browser.isie，是ie浏览器则返回true。
$.each(obj, fn)：通用的迭代函数。可用于近似地迭代对象和数组（代替循环）。
如

代码如下:

$.each( [0,1,2], function(i, n){ alert( “Item #” + i + “: ” + n ); });

等价于：

代码如下:

var tempArr=[0,1,2]; 
for(var i=0;i<tempArr.length;i++){ 
alert(“Item #”+i+”: “+tempArr[ i ]); 
}

也可以处理json数据，如

$.each( { name: “John”, lang: “JS” }, function(i, n){ alert( “Name: ” + i + “, Value: ” + n ); }); 

结果为：
Name:name, Value:John
Name:lang, Value:JS
$.extend(target,prop1,propN)：用一个或多个其他对象来扩展一个对象，返回这个被扩展的对象。这是jquery实现的继承方式。
如：

$.extend(settings, options); 
//合并settings和options，并将合并结果返回settings中，相当于options继承setting并将继承结果保存在setting中。 
var settings = $.extend({}, defaults, options); 
//合并defaults和options，并将合并结果返回到setting中而不覆盖default内容。 

可以有多个参数（合并多项并返回）
$.map(array, fn)：数组映射。把一个数组中的项目(处理转换后)保存到到另一个新数组中，并返回生成的新数组。
如：

var tempArr=$.map( [0,1,2], function(i){ return i + 4; }); 
tempArr内容为：[4,5,6] 
var tempArr=$.map( [0,1,2], function(i){ return i > 0 ? i + 1 : null; }); 
tempArr内容为：[2,3] 
$.merge(arr1,arr2):合并两个数组并删除其中重复的项目。 

如：$.merge( [0,1,2], [2,3,4] ) //返回[0,1,2,3,4]
$.trim(str)：删除字符串两端的空白字符。
如：$.trim(” hello, how are you? “); //返回”hello,how are you? ”
12、解决自定义方法或其他类库与jQuery的冲突
很多时候我们自己定义了$(id)方法来获取一个元素，或者其他的一些js类库如prototype也都定义了$方法，如果同时把这些内容放在一起就会引起变量方法定义冲突，Jquery对此专门提供了方法用于解决此问题。
使 用jquery中的jQuery.noConflict();方法即可把变量$的控制权让渡给第一个实现它的那个库或之前自定义的$方法。之后应用 Jquery的时候只要将所有的$换成jQuery即可，如原来引用对象方法$(“#msg”)改为jQuery(“#msg”)。
如：

代码如下:

jQuery.noConflict(); 
// 开始使用jQuery 
jQuery(“div p”).hide(); 
// 使用其他库的 $() 
$(“content”).style.display = ‘none';

jquery开发过程中经验丰富可以提高开发技巧，所以大家一定要注意平时经验的积累，希望本文所述对大家学习有所帮助。

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