How jquery loads scripts

jQuery is a widely used JavaScript library that provides concise syntax and rich functionality, allowing developers to build interactive web applications faster and easier. When using jQuery to write web applications, we may need to load or manipulate other JavaScript scripts on the page. This article will introduce how to use jQuery to load scripts.

1. jQuery.load()

jQuery.load() is a simple and fast method that can load the HTML fragment of the specified URL into the specified element on the page. In addition to loading HTML elements, the load() method can also be used to load other content, such as JavaScript scripts, CSS files, etc.

When you need to load a JavaScript file, you only need to pass the file URL into the load() method:

$("head").load("https://example.com/myscript.js");

Here we load the script into the head tag of the page. This is a It is a good practice that during the rendering process of the web page, the browser will load all the content in the head tag first, so we can load all the required scripts in the head.

2. $.getScript()

$.getScript() is a method provided by jQuery to load JavaScript scripts. Its usage is not much different from the load() method:

$.getScript("https://example.com/myscript.js", function() {
  // Script has loaded, do something here
});

When we need to perform some operations after the script is loaded, $.getScript() provides a callback function that can perform callback operations after the script is loaded. It should be noted that the $.getScript() method can only load JavaScript scripts and cannot load other types of content.

3. $.ajax()

$.ajax() is one of jQuery’s most powerful methods. It can perform various types of asynchronous HTTP requests, including loading scripts and HTML files. , JSON data, etc.

When loading a JavaScript file, you can use it like this:

$.ajax({
  url: "https://example.com/myscript.js",
  dataType: "script",
  success: function() {
    // Script has loaded, do something here
  }
});

$.ajax() method has a dataType parameter, which represents the data type we want to request. Here we set it to "script" means that what we want to request is a JavaScript script. Similar to the $.getScript() method, the $.ajax() method also provides a callback function to perform a callback operation after the script is loaded.

It should be noted that because the $.ajax() method is relatively complex, improper use will lead to bloated code and difficulty in maintaining. Therefore, in actual development, selection needs to be based on specific circumstances.

Summary

When developing web applications, we often need to load other JavaScript files, including frameworks, plug-ins, component libraries, etc. jQuery provides multiple methods for loading scripts, each with its own pros and cons. When using them, you need to choose the appropriate solution according to the specific situation to avoid bloated code and difficulty in maintaining.

In addition to the methods introduced above, there are other methods of loading scripts, such as dynamically creating script tags, ES6 import statements, etc. In practical applications, it is necessary to choose the most suitable solution according to the specific situation.

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