What functions does javascript achieve?

JavaScript is a programming language widely used in web development and design. It can implement many functions, such as dynamic effects, form validation, operating DOM, increasing interactivity, etc. This article will introduce the main functions implemented by JavaScript.

1. Dynamic effects

JavaScript can achieve various dynamic effects. For example, pop-up windows, expand and collapse menus, drag and drop effects, image carousels, etc. Among them, the most common dynamic effects are fade in and fade out and sliding effects.

Fade in and out means that an element slowly changes from transparent to opaque, or from opaque to transparent over time. The sliding effect is when the position of an element slowly moves from one position to another over time.

2. Form Validation

JavaScript can also be used to validate forms to ensure that the data entered by the user complies with regulations. For example, when a user submits a form, it can be checked whether the required fields are empty, whether the password meets the requirements, whether the email format is correct, etc. If the input does not meet the requirements, JavaScript will pop up a prompt box to remind the user how to correct the input.

3. Operation DOM

JavaScript can easily operate elements in HTML documents, making the page more dynamic and interactive. Through JavaScript, you can get the attributes, styles, text values, etc. of HTML elements. At the same time, these values ​​can also be modified dynamically, elements can be added or deleted, and page content can be updated based on user operations.

4. AJAX

AJAX is a technology that uses JavaScript and the XMLHttpRequest object to obtain data from the server without refreshing the page. Through AJAX, the page can be made smoother and the user experience better. For example, when a user wants to view other pages or request some data, AJAX can load data in the background and display the data on the page without refreshing the entire page.

5. Cookie Operation

JavaScript can track user behavior through cookies. Cookie is a small text file that is saved on the user's computer and records the user's personal preferences, login status, shopping cart contents, etc. You can set Cookie values, obtain Cookie values, and delete Cookies through JavaScript to provide users with better services.

In addition to the main functions mentioned above, JavaScript can also implement other functions, such as controlling page transfer, image processing, audio and video playback, game development, etc. The diversity and flexibility of JavaScript functions make it an important part of web development. It is not only suitable for PC-side development, but can also be widely used in mobile-side development.

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