There are primarily four things we need to cover to understand how the vector layer works.
Let's go over rendering—fortunately, there's not much to it.
As we discussed earlier, the vector layer doesn't use raster graphics. Other layer types use the <img> tag (image tag) to show images—in HTML, the image tag will only display raster images. So, we can't just use <img> tags like other layers. Instead, we have to use a vector image renderer. As we mentioned before, the vector data is not just an image, and can contain additional information such as the coordinates of the data.
The vector data must be rendered to be seen. OpenLayers supports three ways to render the vector layer: SVG, Canvas, and VML.