The method works by calling the “previousSibling” property of a given element and returning the previous sibling node of that element. This can be especially useful when you need to manipulate elements that are located right before a specific node, without having to traverse the entire tree.
At the top of the DOM tree is the
document node, which represents the entire HTML document. Below that are a series of child nodes, each representing an HTML element. The nodes can have parent, child, and sibling relationships with other nodes in the tree, depending on their position in the HTML markup.
querySelector(). Once you have a reference to a node, you can manipulate its attributes, content, and position within the tree using a variety of properties and methods.
To select the previous sibling element, you can use the parentNode property to target the parent element, and then use the previousSibling property to get the previous sibling element. For example, if you have the following HTML code:
let wrapper = document.querySelector(“.wrapper”);
let previousSibling = wrapper.parentNode.previousSibling;
In this example, the variable previousSibling will contain the first child of the parent element, which is the text node containing the newline character.
If you want to select the previous sibling element that is an HTML element rather than a text node, you can use the previousElementSibling property. For example:
let previousElementSibling = wrapper.previousElementSibling;
This code will select the previous sibling element with the class “wrapper”.
- Always double-check the syntax of your code before implementing it. A single typo can break your code and cause unexpected issues.
- Use comments within your code to keep it organized and easy to understand. This can be especially helpful when working on a large project or collaborating with others.
- Be mindful of the performance impact of using the Previous Sibling method. When working with large web pages, repeatedly calling this method can slow down the user’s experience and lead to frustration.
- Consider using an alternative method, such as parent-child relationships or IDs, if it would be more efficient or effective for your specific use case.
- Always test your code in different scenarios and browsers to ensure it functions properly for all users.
querySelector methods are usually enough to achieve this, there are some alternative ways that can make your code cleaner or more efficient:
previousElementSiblingproperties: These properties allow us to access the next or previous sibling element node instead of the next or previous sibling node, which could be a text or comment node. This can be particularly useful when you are looping through a collection of elements.
closestmethod: This method allows us to traverse up the DOM tree, starting from the current element, and find the first ancestor that matches a selector. This is similar to using
childrenproperty: This property returns a collection of all child elements of the current element. This can be more efficient than using
childNodesand filtering out text and comment nodes.
previousAllmethods: These methods return all the sibling elements that come after or before the current element, respectively. This can be useful when you need to access multiple siblings at once.