What does it mean to render css
From above this figure, we can see that a few things:
1) the browser will parse three things:
One is the HTML / SVG / XHTML, in fact, Webkit three C ++ classes corresponding to these three documents. These three documents will have to resolve a DOM Tree. CSS, CSS parsing will produce CSS rules tree.
Javascript, script, mainly to operate DOM Tree and CSS Rule Tree by DOM API and CSSOM API.
2) After the completion of the analysis, the browser engine can be constructed by DOM Tree Rendering Tree and CSS Rule Tree. note:
Rendering Tree render tree is not the same DOM tree, or as some like Header display: none no need to put things in the render tree.
The CSS Rule Tree is mainly to complete the match and put on each Element additional CSS Rule on Rendering Tree. That is DOM node. Also known as Frame.
It is then calculated for each Frame (i.e. per Element) position, which is also called reflow process and layout.
3) Finally, draw by calling the operating system Native GUI API.
Top of your browser to load and display process and principles from the point of view of a web page, we can know: css rendering is the browser parses the HTML document generation dom parse tree and generate css css rule tree, the last generation rendering tree, drawing to the screen through the system api the process of.