Web Development 1.3 - Creating Elements Using the DOM
Summary
TLDRIn this lesson, you'll learn how to interact with HTML elements using the DOM. We explore accessing existing elements, modifying content with `innerHTML`, and creating new elements using `createElement`. You'll also learn how to add new elements to a page using `appendChild` and `insertBefore`, placing them exactly where you want. The lesson explains helpful DOM navigation methods like `firstElementChild`, `lastElementChild`, and `parentElement`, to easily traverse and manipulate the structure. By the end, you'll be able to dynamically modify and create HTML content, with examples to practice your new skills.
Takeaways
- 😀 The Document Object Model (DOM) allows us to manipulate HTML elements using JavaScript.
- 😀 The 'document' keyword provides direct access to elements like title and body in an HTML file.
- 😀 '.innerHTML' is used to access and change the content of an existing HTML element.
- 😀 The 'createElement' function allows you to create new HTML elements dynamically using JavaScript.
- 😀 The 'createElement' function requires a string parameter that specifies the type of element to create (e.g., 'p' for paragraph).
- 😀 Newly created elements, like a <p> tag, start off without any content or attributes.
- 😀 To add content to a new element, you can modify its '.innerHTML' property.
- 😀 The 'appendChild' function adds a newly created element as the last child of a specified parent element (e.g., the body).
- 😀 'insertBefore' allows you to add a new element before an existing one within a parent element.
- 😀 Helper methods like '.firstElementChild', '.lastElementChild', '.children', and '.parentElement' assist in navigating and accessing parent and child elements in the DOM.
- 😀 JavaScript’s DOM manipulation enables creating and positioning new elements dynamically in a webpage, improving interactivity and structure.
Q & A
What is the purpose of the Document Object Model (DOM)?
-The DOM is a programming interface for HTML and XML documents. It represents the document as a tree structure where each element is a node. It allows us to interact with and manipulate the structure, style, and content of web pages dynamically.
How can you access HTML elements using the DOM?
-You can access HTML elements using the `document` object, followed by the element's identifier or type. For example, `document.title` accesses the title of the page, and `document.body` accesses the body of the HTML document.
What does the `.innerHTML` property do?
-.innerHTML allows you to access and modify the HTML content of an element. By setting `innerHTML`, you can update the content inside an element, like text or HTML tags.
What is the purpose of the `createElement` method?
-The `createElement` method creates a new HTML element as a JavaScript object. The new element is not yet part of the page, but it can be customized and added later.
How can you add newly created elements to a webpage?
-You can use methods like `appendChild` and `insertBefore` to add newly created elements to the DOM. `appendChild` adds the element to the end of the parent element, while `insertBefore` allows you to insert the new element before a specified child.
What is the difference between `appendChild` and `insertBefore`?
-`appendChild` adds a new element as the last child of the specified parent element. `insertBefore`, on the other hand, allows you to specify where the new element should be placed, before an existing child element.
Can you explain how to use `insertBefore` with an example?
-To use `insertBefore`, first identify the parent element and the reference element before which you want to insert the new element. For example, to insert a subtitle before a paragraph with the ID `essay`, you would use `document.body.insertBefore(subtitle, essay);`
What are some useful helper methods for navigating the DOM?
-Some useful DOM navigation methods include `.firstElementChild` (returns the first child element), `.lastElementChild` (returns the last child element), `.children` (returns a collection of all child elements), and `.parentElement` (returns the parent element of the current element).
How do you find the first and last child elements of an element?
-To find the first and last child elements of an element, you can use `firstElementChild` and `lastElementChild`. For example, `document.body.firstElementChild` gives the first child of the body, and `document.body.lastElementChild` gives the last.
How can you identify an element's parent using the DOM?
-You can identify an element's parent using the `.parentElement` property. For example, if you have a reference to a child element, you can access its parent element like this: `childElement.parentElement`.
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