The critical rendering path (CRP) looks at the sequence of steps the browser takes to receive HTML, CSS, and JavaScript bytes, as well as the techniques required to render the initial view of the web page.
There are 6 stages to the CRP –
Constructing the DOM Tree Constructing the CSSOM Tree Running JavaScript Creating the Render Tree Generating the Layout Painting
In order to display a webpage, a browser must get all the resources that are called by the webpage. A simple example would be a webpage that has one image, one css file, and one javascript file.
Let’s look at the path that this page takes before it gets displayed….
browser downloads the html file browser reads the html and sees that there are one css file, one javascript file and one image browser starts downloading the image browser decides it can not display the webpage without first getting the css and javascript browser downloads the CSS file and reads it to make sure nothing else is being called browser decides it still can not display the webpage yet until it has the javascript browser downloads the javascript file and reads it to make sure nothing else is being called Browser now decides it can display the webpage
####. CSS Object Model (CSSOM)
Just as with HTML, the CSS rules need to be converted into something that the browser understands, so these rules go through the same steps as the document object model.
- Convert bytes to characters
- Identify tokens
- Convert tokens to nodes
- Build CSSOM
Further Reading
https://varvy.com/pagespeed/critical-render-path.html
Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices.
