jQuery

What is jQuery?

jQuery is a freely available JavaScript library that offers web developers a variety of function groups. The function groups allow a so-called manipulation of the existing page or app. It extends JavaScript with additional functions, and is therefore not a programming language in its own right. jQuery facilitates the work of web developers, as the various browsers often have technical differences. The display of a website or app can vary greatly as a result. To avoid this and save the developer the extra work, jQuery bridges these differences with a compact and uniform code.
jQuery was developed by John Resig and first introduced in early 2006. Since then, this open source solution has been constantly evolving and is regularly updated.

What can be done with jQuery?

The jQuery class library provides the website developer with simplified access to many Document Object Model (DOM) functions. The DOM is a standardized programming interface in which the structures of HTML and XML documents are merged. The uncomplicated integration of jQuery functions saves web developers a lot of time, which they would otherwise have to invest in complex code. Also, the implementation makes it easier to access the HTML source code and make adjustments.
In general, this can be simple adjustments, such as changing a color or the position of an object. However, more complex manipulations of the DOM in terms of animation or actions by the user are also possible.

jQuery and AJAX

With jQuery, the content of your website or app can be built event-driven. This allows you to react to the user's behavior at any time. With an additional integration of AJAX (Asynchronous Java-Script and XML), a fast connection to the server can be established. This allows information about the user's action or input to be processed more quickly and sent to the PHP backend. The server processes this information and thereby outputs the next step to the user. AJAX enables asynchronous transfer of data between server and browser. Modified content can thus be played out for the user without having to reload the entire page.
One of the best-known applications of AJAX is Google Search, for example. Using the Google Suggest service, your query is recognized by Google and further suggestions for completing your question are already displayed during your search.
Another example are online stores, which offer you products for individual design. The articles can often be designed simply by drag-and-drop. AJAX is used in combination with jQuery, so that the page is not reloaded after each of your mouse clicks.

You probably encounter both in combination every day when surfing the Internet without noticing it. We have become very accustomed to both implementations, and we can't imagine life without them.