innerHTML = '...' vs appendChild(txtNode): When Should You Use Each Method?

"innerHTML = ..." vs "appendChild(txtNode)"

In the realm of web development, modifying the content of HTML elements is a common task. Two widely-used methods for this purpose are innerHTML assignment and appending text nodes. However, these methods have distinct characteristics that impact performance and behavior.

innerHTML Assignment

Setting the innerHTML property directly modifies the entire content of the target element. This process involves parsing the provided HTML string and rebuilding the element's DOM structure. Consequently, innerHTML assignment triggers a complete reflow of the element and its descendants, potentially affecting the layout and rendering of the page.

Furthermore, innerHTML assignment invalidates all existing references to child nodes within the target element. This is because the old nodes are essentially replaced by the newly generated ones.

appendChild()

Contrarily, appending a text node via appendChild() does not cause a full DOM rebuild. Instead, it simply appends the specified text content to the existing element. This results in a more localized reflow, affecting only the immediate area where the text was added.

Unlike innerHTML assignment, appendChild() preserves references to existing nodes. This is because it does not modify the structure of the DOM; rather, it adds new content without disrupting the existing tree.

Performance Considerations

In general, appendChild() is considered more efficient for appending content to existing elements. Since it avoids the cost of parsing and rebuilding the DOM, it incurs less overhead. However, in certain scenarios, such as replacing the entire content of an element, innerHTML assignment may be more convenient.

Alternative Options

In addition to innerHTML and appendChild(), there are several alternative methods for manipulating DOM content:

• insertAdjacentHTML(): This method allows you to insert HTML content into or adjacent to the specified element.
• insertAdjacentText(): Similar to insertAdjacentHTML(), but inserts plain text instead of HTML.
• append(): A newer addition to the DOM API, the append() method appends one or more items as child nodes to the specified element.

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