Benchmark: style.getPropertyValue vs. getBoundingClientRect

HTML Preparation code:

<div id="foo">some content <div>text</div> yet one more</div>

Tests:

style.getPropertyValue
var i = 5000; var elm = document.getElementById('foo'); while (i--) { checkDisplay(elm); } function checkDisplay(elm) { return parseInt(elm.style.getPropertyValue('width'), 10) === 0; }
getBoundingClientRect
var i = 5000; var elm = document.getElementById('foo'); while (i--) { checkDisplay(elm); } function checkDisplay(elm) { return Math.floor(elm.getBoundingClientRect().width) === 0; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
style.getPropertyValue
getBoundingClientRect

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:131.0) Gecko/20100101 Firefox/131.0

Browser/OS: Firefox 131 on Linux

View result in a separate tab

Test name	Executions per second
style.getPropertyValue	3737.0 Ops/sec
getBoundingClientRect	683.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark provided is focused on comparing two different methods of obtaining style properties from an HTML element in the DOM (Document Object Model). Specifically, it compares `style.getPropertyValue` against `getBoundingClientRect`. The benchmark runs 5,000 iterations of each method to measure their performance, specifically how many executions can be completed in one second.

### Options Being Compared

1. **style.getPropertyValue():**
   - **Functionality:** This method is used to retrieve the value of a CSS property from the inline styles of an element. In this benchmark, it specifically checks the `width` property of the element with the ID `foo`.
   - **Pros:** 
     - **Simplicity:** This method is straightforward and works well for getting inline styles.
     - **Performance:** Depending on the context, it may offer better performance for accessing style properties directly set on the element.
   - **Cons:** 
     - **Limited Scope:** It only returns the value of the property as defined in the element’s style attribute, not what is affected by external stylesheets or browser default styles.
     - **Does Not Compute Final Rendered Value:** It doesn’t account for styles inherited from other stylesheets that may affect the final rendering.

2. **getBoundingClientRect():**
   - **Functionality:** This method returns a DOMRect object that contains the size of an element and its position relative to the viewport. The benchmark checks the `width` property of the returned object, which includes calculated styles.
   - **Pros:** 
     - **Comprehensive:** Provides the actual dimensions of the element as rendered on the page, considering all CSS styles.
     - **Useful for Layout Calculations:** Essential for layouts, animations, and any graphic manipulations where physical size and position are necessary.
   - **Cons:** 
     - **Performance:** It may be slower than accessing inline styles because it requires calculating the layout, which may involve more processing.
     - **Layout Thrashing:** Frequent calls can lead to layout recalculations, which might degrade performance if called excessively.

### Additional Considerations
- **Performance Outcomes:** Based on the results shared, `style.getPropertyValue` significantly outperforms `getBoundingClientRect`. In a real-world application where performance affects user experience, choosing the right method based on what's needed (actual style vs computed layout) is crucial.
- **Context of Use:** The choice between the two methods often depends on the context—if you're only concerned with inline styles, `style.getPropertyValue` might be the better choice. If you need to know the actual rendered size, `getBoundingClientRect` is necessary.
- **Further Alternatives:** 
  - **Computed Style:** Another method to consider is `window.getComputedStyle(elm).width`, which retrieves the computed style, including styles from stylesheets. It offers a balance but may have performance implications similar to `getBoundingClientRect` since it computes styles.

### Conclusion
For software engineers, especially those working on performance-critical applications, understanding the differences between these methods is essential. The benchmark highlights the trade-offs between accessing properties directly versus getting computed values, guiding the choice based on specific needs in layout, rendering, and performance.

Related benchmarks:

style.getPropertyValue vs. getBoundingClientRect (version: 0)

Comparing performance of: style.getPropertyValue vs getBoundingClientRect

Created: one year ago by: Guest

Jump to the latest result

style.getPropertyValue

getBoundingClientRect

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):