When Should You Use jQuery\'s `document.ready` Function?

When Should You Use jQuery's document.ready Function?

jQuery's document.ready function allows you to execute code when the HTML document has fully loaded and is ready to be manipulated. It serves a crucial role in JavaScript and jQuery development, ensuring that DOM manipulation occurs at the appropriate time.

When to Use document.ready

It's generally advisable to wrap your JavaScript/jQuery code within document.ready when:

• Manipulating the DOM: Since document.ready waits for the document to finish loading, it guarantees that DOM elements are present before attempting to access or modify them.
• Using .on() Event Handlers: Except when used on the document itself, click handlers for .on() should be placed within document.ready to ensure proper event binding.
• Preventing Accessibility Issues: JavaScript code that alters the page's appearance or content should be run within document.ready to ensure accessibility for users with disabilities who rely on assistive technologies.

Performance Impact

Placing code within document.ready does not significantly impact performance. jQuery optimizes its execution to avoid performance penalties.

Object Scope and AJAX

• Objects declared within document.ready have a limited scope to the context of the initial page.
• When an AJAX-loaded page replaces the content, objects from the previous page's document.ready are no longer accessible.
• To maintain access to objects across AJAX page transitions, place them outside of document.ready, making them truly global.

Bottom-of-Page JavaScript Placement and defer Attribute

Placing JavaScript at the bottom of your HTML page, along with using defer attributes for jQuery scripts on AJAX-loaded pages, are best practices. They ensure the necessary resources are available before executing code.

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