Usage analysis of jQuery() method in jQuery_jquery

The examples in this article describe the usage of the jQuery() method in jQuery. Share it with everyone for your reference. The details are as follows:

Definition and usage of jQuery() method:
This method can accept a set of selectors to match the corresponding elements. For example:

Copy code The code is as follows:

jQuery("div")

In practical applications, $ is generally used to define jQuery. In fact, $ is the abbreviation of jQuery. For example, $("li") can be written as jQuery("li").
The core functions of jQuery are all implemented through this method, or are implemented using this method in some way. The following is a detailed introduction to the usage of this method.
Grammar structure 1:
When the jQuery() method does not have any parameters, it will return an empty jQuery object.

Copy code The code is as follows:

jQuery()

Example code:

Copy code The code is as follows:

Click to see the effect

Grammar structure 2:

Copy code The code is as follows:

jQuery(selector,context)

Parameter list:

参数	描述
selector	用来匹配元素的选择器。
context	可选。待查找的DOM元素集、文档或者jQuery对象。 如果没有指定，则就是当前整个文档。

If not specified, it is the entire current document.

Example code:
Example 1:

Copy code The code is as follows:

• DIV CSS Zone


• jQuery Zone


• HTML Zone

• ASP Zone


• Script HouseWelcome

The sun is out

Click to see the effect

The above code can set the font color in the li element to red.
Example 2:

Copy code The code is as follows:

• DIV CSS Zone


• jQuery Zone


• HTML Zone

• ASP Zone


• Script HouseWelcome

The sun is out

Click to see the effect

The above code sets the font color in the li element in the div to red.
Grammar structure three:
Convert DOM elements and DOM element arrays into jQuery objects.

Copy code The code is as follows:

jQuery(element|elementArray)

Parameter list:

参数	描述
element	要转换成jQuery对象的DOM元素。
elementArray	要转换成jQuery对象的DOM元素数组。

Example code:
Example 1:

Copy code The code is as follows:

• DIV CSS area


• jQuery Zone


• HTML Zone

• ASP Zone


• Script HouseWelcome

The sun is out

Click to see the effect

The above code can set the font color in the li element with id first to red.
Example 2:

Copy code The code is as follows:

• DIV CSS area


• jQuery Zone


• HTML Zone

• ASP Zone


• Script HouseWelcome

The sun is out

Click to see the effect

Grammar structure four:

Copy code The code is as follows:

jQuery(callback)

jQuery (callback) is the abbreviation of $(document).ready(), which is used in several examples above.
Its function is to execute the callback function
after the document is loaded. Parameter list:

参数	描述
callback	文档加载完成之后要执行的函数。

Example code:

Copy code The code is as follows:

Copy code The code is as follows:

jQuery(function(){
alert("Document loading completed");
})

The function is the same as the following code:

Copy code The code is as follows:

$(document).ready(function(){
alert("Document loading completed");
})

I hope this article will be helpful to everyone’s jQuery programming.