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

innerHTML = ... vs appendChild(txtNode)

When it comes to modifying the content of an HTML element, developers often use either the "innerHTML = ..." or "appendChild(txtNode)" method. Both techniques result in adding new content to an existing node, but they differ in their underlying mechanisms and effects on the DOM.

innerHTML = ...

This method appends the specified HTML string to the end of the target element's innerHTML property. It involves parsing the HTML string, creating DOM nodes, and inserting them into the existing node. This process triggers a reflow, which means that the browser recalculates the layout of the modified element and possibly its descendants.

appendChild(txtNode)

This method takes a pre-created DOM node (typically a TextNode) and inserts it as a child of the target element. It avoids parsing HTML strings and directly modifies the DOM tree. This approach does not cause a reflow unless the inserted node has significant dimensions or affects the layout in some way.

Comparison

• DOM Manipulation: appendChild directly manipulates the DOM tree, ensuring references to child nodes remain intact. Alternatively, innerHTML recreates the entire content of the target element, potentially breaking existing references.
• Performance: With small modifications to the end of an element, innerHTML may be faster due to the browser's efficient HTML parsing. Conversely, appendChild becomes more performant for substantial content insertions or when modifying specific nodes.
• Simplicity: appendChild is generally simpler to use and less likely to cause unexpected side effects.
• Alternatives: Alternative methods like element.append() and insertAdjacentHTML provide additional options with different capabilities depending on the scenario.

In conclusion, appendChild is the preferred method for appending content or modifying DOM nodes when maintaining existing references is crucial. However, in specific circumstances (such as simple content insertions after an element), innerHTML may offer performance benefits. When replacing content or inserting complex HTML, using DOM manipulation directly may be more appropriate.

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