An in-depth discussion of the functions and uses of the $ symbol in jQuery

The

$ symbol is a very important symbol in jQuery. It is the core identifier of jQuery and is used to represent jQuery’s global variables. In jQuery, the $ sign works similarly to the $ sign in other JavaScript frameworks. When you see the $ sign, you know you're using jQuery. The

$ symbol has many functions. Several common applications and features will be introduced in detail below.

1. Selector function
$ symbol is mainly used for selector function in jQuery. By using the $ symbol with the selector, you can quickly select DOM elements. For example, the following code example can be used to select the element with the id of example:

$("#example")

$("#example") here is equivalent to document.getElementById("example").

2. Event processing
$ symbol can also be used for event processing. Through the event method of $ symbol, event monitoring and processing of DOM elements can be realized. For example, the following code example can be used to realize the function of clicking a button to pop up a prompt box:

$("#btn").click(function() {
    alert("Hello, jQuery!");
});

3. DOM operation
   $ symbol can also be used for DOM operations, through the DOM operation method of the $ symbol , which can implement operations such as adding, deleting, modifying, and checking DOM elements. For example, the following code example can be used to add a new piece of data to the list:

   $("ul").append("<li>New Item</li>");

4. AJAX request
   $ symbol can also be used to initiate an AJAX request, through the AJAX method of the $ symbol , which can realize data interaction with the server. For example, the following code example can be used to send a GET request to the server and obtain data:

   $.ajax({
    url: "https://api.example.com/data",
    method: "GET",
    success: function(data) {
        console.log(data);
    }
   });

5. Chained operation
   $The symbol supports chained operations, that is, in a selector or Continue to use the $ symbol after the method. This enables the combination of multiple operations. For example, in the following code example, the element with the id of example is first selected and then its text content is set:

   $("#example").text("Hello, jQuery!").css("color", "red");

In general, the $ symbol plays a very important role in jQuery. Its concise and efficient syntax allows developers to quickly and easily implement various DOM operations and event processing. Through the various applications and features of the $ symbol, development efficiency can be greatly improved, and it is one of the indispensable tools in front-end development.

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